diff --git a/apps/participation/apps.py b/apps/participation/apps.py
index 98690b3..e775176 100644
--- a/apps/participation/apps.py
+++ b/apps/participation/apps.py
@@ -3,6 +3,9 @@ from django.db.models.signals import post_save, pre_delete, pre_save
 
 
 class ParticipationConfig(AppConfig):
+    """
+    The participation app contains the data about the teams, videos, ...
+    """
     name = 'participation'
 
     def ready(self):
diff --git a/apps/participation/forms.py b/apps/participation/forms.py
index 907e9fd..fdc9802 100644
--- a/apps/participation/forms.py
+++ b/apps/participation/forms.py
@@ -9,6 +9,10 @@ from .models import Participation, Phase, Team, Video
 
 
 class TeamForm(forms.ModelForm):
+    """
+    Form to create a team, with the name and the trigram,
+    and if the team accepts that Animath diffuse the videos.
+    """
     def clean_trigram(self):
         trigram = self.cleaned_data["trigram"].upper()
         if not re.match("[A-Z]{3}", trigram):
@@ -21,6 +25,9 @@ class TeamForm(forms.ModelForm):
 
 
 class JoinTeamForm(forms.ModelForm):
+    """
+    Form to join a team by the access code.
+    """
     def clean_access_code(self):
         access_code = self.cleaned_data["access_code"]
         if not Team.objects.filter(access_code=access_code).exists():
@@ -40,12 +47,18 @@ class JoinTeamForm(forms.ModelForm):
 
 
 class ParticipationForm(forms.ModelForm):
+    """
+    Form to update the problem of a team participation.
+    """
     class Meta:
         model = Participation
         fields = ('problem',)
 
 
 class RequestValidationForm(forms.Form):
+    """
+    Form to ask about validation.
+    """
     _form_type = forms.CharField(
         initial="RequestValidationForm",
         widget=forms.HiddenInput(),
@@ -58,6 +71,9 @@ class RequestValidationForm(forms.Form):
 
 
 class ValidateParticipationForm(forms.Form):
+    """
+    Form to let administrators to accept or refuse a team.
+    """
     _form_type = forms.CharField(
         initial="ValidateParticipationForm",
         widget=forms.HiddenInput(),
@@ -70,6 +86,9 @@ class ValidateParticipationForm(forms.Form):
 
 
 class UploadVideoForm(forms.ModelForm):
+    """
+    Form to upload a video, for a solution or a synthesis.
+    """
     class Meta:
         model = Video
         fields = ('link',)
@@ -81,6 +100,9 @@ class UploadVideoForm(forms.ModelForm):
 
 
 class PhaseForm(forms.ModelForm):
+    """
+    Form to update the calendar of a phase.
+    """
     class Meta:
         model = Phase
         fields = ('start', 'end',)
diff --git a/apps/participation/models.py b/apps/participation/models.py
index 41aa5c2..322fb9a 100644
--- a/apps/participation/models.py
+++ b/apps/participation/models.py
@@ -17,6 +17,10 @@ from nio import RoomPreset, RoomVisibility
 
 
 class Team(models.Model):
+    """
+    The Team model represents a real team that participates to the Correspondances.
+    This only includes the registration detail.
+    """
     name = models.CharField(
         max_length=255,
         verbose_name=_("name"),
@@ -45,9 +49,15 @@ class Team(models.Model):
 
     @property
     def email(self):
+        """
+        :return: The mailing list to contact the team members.
+        """
         return f"equipe-{self.trigram.lower()}@{os.getenv('SYMPA_HOST', 'localhost')}"
 
     def create_mailing_list(self):
+        """
+        Create a new Sympa mailing list to contact the team.
+        """
         get_sympa_client().create_list(
             f"equipe-{self.trigram.lower()}",
             f"Équipe {self.name} ({self.trigram})",
@@ -58,10 +68,15 @@ class Team(models.Model):
         )
 
     def delete_mailing_list(self):
+        """
+        Drop the Sympa mailing list, if the team is empty or if the trigram changed.
+        """
         get_sympa_client().delete_list(f"equipe-{self.trigram}")
 
     def save(self, *args, **kwargs):
         if not self.access_code:
+            # if the team got created, generate the access code, create the contact mailing list
+            # and create a dedicated Matrix room.
             self.access_code = get_random_string(6)
             self.create_mailing_list()
 
@@ -90,6 +105,10 @@ class Team(models.Model):
 
 
 class Participation(models.Model):
+    """
+    The Participation model contains all data that are related to the participation:
+    chosen problem, validity status, videos,...
+    """
     team = models.OneToOneField(
         Team,
         on_delete=models.CASCADE,
@@ -149,6 +168,9 @@ class Participation(models.Model):
 
 
 class Video(models.Model):
+    """
+    The Video model only contains a link and a validity status.
+    """
     link = models.URLField(
         verbose_name=_("link"),
         help_text=_("The full video link."),
@@ -163,23 +185,38 @@ class Video(models.Model):
 
     @property
     def participation(self):
+        """
+        Retrives the participation that is associated to this video,
+        whatever it is a solution or a synthesis.
+        """
         try:
+            # If this is a solution
             return self.participation_solution
         except ObjectDoesNotExist:
+            # If this is a synthesis
             return self.participation_synthesis
 
     @property
     def platform(self):
+        """
+        According to the link, retrieve the platform that is used to upload the video.
+        """
         if "youtube.com" in self.link or "youtu.be" in self.link:
             return "youtube"
         return "unknown"
 
     @property
     def youtube_code(self):
+        """
+        If the video is uploaded on Youtube, search in the URL the video code.
+        """
         return re.compile("(https?://|)(www\\.|)(youtube\\.com/watch\\?v=|youtu\\.be/)([a-zA-Z0-9-_]*)?.*?")\
             .match("https://www.youtube.com/watch?v=73nsrixx7eI").group(4)
 
     def as_iframe(self):
+        """
+        Generate the HTML code to embed the video in an iframe, according to the type of the host platform.
+        """
         if self.platform == "youtube":
             return render_to_string("participation/youtube_iframe.html", context=dict(youtube_code=self.youtube_code))
         return None
@@ -194,6 +231,9 @@ class Video(models.Model):
 
 
 class Phase(models.Model):
+    """
+    The Phase model corresponds to the dates of the phase.
+    """
     phase_number = models.AutoField(
         primary_key=True,
         unique=True,
@@ -217,6 +257,9 @@ class Phase(models.Model):
 
     @classmethod
     def current_phase(cls):
+        """
+        Retrieve the current phase of this day
+        """
         qs = Phase.objects.filter(start__lte=timezone.now(), end__gte=timezone.now())
         if qs.exists():
             return qs.get()
diff --git a/apps/participation/search_indexes.py b/apps/participation/search_indexes.py
index c1a2249..734d5bb 100644
--- a/apps/participation/search_indexes.py
+++ b/apps/participation/search_indexes.py
@@ -4,6 +4,9 @@ from .models import Participation, Team, Video
 
 
 class TeamIndex(indexes.ModelSearchIndex, indexes.Indexable):
+    """
+    Index all teams by their name and trigram.
+    """
     text = indexes.NgramField(document=True, use_template=True)
 
     class Meta:
@@ -11,6 +14,9 @@ class TeamIndex(indexes.ModelSearchIndex, indexes.Indexable):
 
 
 class ParticipationIndex(indexes.ModelSearchIndex, indexes.Indexable):
+    """
+    Index all participations by their team name and team trigram.
+    """
     text = indexes.NgramField(document=True, use_template=True)
 
     class Meta:
@@ -18,6 +24,9 @@ class ParticipationIndex(indexes.ModelSearchIndex, indexes.Indexable):
 
 
 class VideoIndex(indexes.ModelSearchIndex, indexes.Indexable):
+    """
+    Index all teams by their team name and team trigram.
+    """
     text = indexes.NgramField(document=True, use_template=True)
 
     class Meta:
diff --git a/apps/participation/signals.py b/apps/participation/signals.py
index d8caa42..a7ee7d4 100644
--- a/apps/participation/signals.py
+++ b/apps/participation/signals.py
@@ -3,6 +3,9 @@ from participation.models import Participation, Team, Video
 
 
 def create_team_participation(instance, **_):
+    """
+    When a team got created, create an associated team and create Video objects.
+    """
     participation = Participation.objects.get_or_create(team=instance)[0]
     if not participation.solution:
         participation.solution = Video.objects.create()
@@ -12,11 +15,17 @@ def create_team_participation(instance, **_):
 
 
 def update_mailing_list(instance: Team, **_):
+    """
+    When a team name or trigram got updated, update mailing lists and Matrix rooms
+    """
     if instance.pk:
         old_team = Team.objects.get(pk=instance.pk)
         if old_team.name != instance.name or old_team.trigram != instance.trigram:
+            # TODO Rename Matrix room
+            # Delete old mailing list, create a new one
             old_team.delete_mailing_list()
             instance.create_mailing_list()
+            # Subscribe all team members in the mailing list
             for student in instance.students.all():
                 get_sympa_client().subscribe(student.user.email, f"equipe-{instance.trigram.lower()}", False,
                                              f"{student.user.first_name} {student.user.last_name}")
diff --git a/apps/participation/tests.py b/apps/participation/tests.py
index 8ff219a..abd8dd7 100644
--- a/apps/participation/tests.py
+++ b/apps/participation/tests.py
@@ -34,6 +34,9 @@ class TestStudentParticipation(TestCase):
         str(self.team.participation)
 
     def test_create_team(self):
+        """
+        Try to create a team.
+        """
         response = self.client.get(reverse("participation:create_team"))
         self.assertEqual(response.status_code, 200)
 
@@ -61,6 +64,9 @@ class TestStudentParticipation(TestCase):
         ))
 
     def test_join_team(self):
+        """
+        Try to join an existing team.
+        """
         response = self.client.get(reverse("participation:join_team"))
         self.assertEqual(response.status_code, 200)
 
@@ -84,10 +90,16 @@ class TestStudentParticipation(TestCase):
         self.assertEqual(response.status_code, 403)
 
     def test_no_myteam_redirect_noteam(self):
+        """
+        Test redirection.
+        """
         response = self.client.get(reverse("participation:my_team_detail"))
         self.assertTrue(response.status_code, 200)
 
     def test_team_detail(self):
+        """
+        Try to display the information of a team.
+        """
         self.user.registration.team = self.team
         self.user.registration.save()
 
@@ -98,6 +110,9 @@ class TestStudentParticipation(TestCase):
         self.assertEqual(response.status_code, 200)
 
     def test_update_team(self):
+        """
+        Try to update team information.
+        """
         self.user.registration.team = self.team
         self.user.registration.save()
 
@@ -123,10 +138,16 @@ class TestStudentParticipation(TestCase):
         self.assertTrue(Team.objects.filter(trigram="BBB", participation__problem=3).exists())
 
     def test_no_myparticipation_redirect_nomyparticipation(self):
+        """
+        Ensure a permission denied when we search my team participation when we are in no team.
+        """
         response = self.client.get(reverse("participation:my_participation_detail"))
-        self.assertTrue(response.status_code, 200)
+        self.assertEqual(response.status_code, 403)
 
     def test_participation_detail(self):
+        """
+        Try to display the detail of a team participation.
+        """
         self.user.registration.team = self.team
         self.user.registration.save()
 
@@ -146,6 +167,9 @@ class TestStudentParticipation(TestCase):
         self.assertEqual(response.status_code, 200)
 
     def test_upload_video(self):
+        """
+        Try to send a solution video link.
+        """
         self.user.registration.team = self.team
         self.user.registration.save()
 
@@ -178,21 +202,30 @@ class TestAdminForbidden(TestCase):
         self.client.force_login(self.user)
 
     def test_create_team_forbidden(self):
+        """
+        Ensure that an admin can't create a team.
+        """
         response = self.client.post(reverse("participation:create_team"), data=dict(
             name="Test team",
             trigram="TES",
             grant_animath_access_videos=False,
         ))
-        self.assertTrue(response.status_code, 200)
+        self.assertEqual(response.status_code, 403)
 
     def test_join_team_forbidden(self):
+        """
+        Ensure that an admin can't join a team.
+        """
         team = Team.objects.create(name="Test", trigram="TES")
 
         response = self.client.post(reverse("participation:join_team"), data=dict(
             access_code=team.access_code,
         ))
-        self.assertTrue(response.status_code, 200)
+        self.assertTrue(response.status_code, 403)
 
     def test_my_team_forbidden(self):
+        """
+        Ensure that an admin can't access to "My team".
+        """
         response = self.client.get(reverse("participation:my_team_detail"))
-        self.assertTrue(response.status_code, 200)
+        self.assertEqual(response.status_code, 403)
diff --git a/apps/participation/views.py b/apps/participation/views.py
index 1353c39..758136b 100644
--- a/apps/participation/views.py
+++ b/apps/participation/views.py
@@ -27,6 +27,10 @@ from .tables import CalendarTable
 
 
 class CreateTeamView(LoginRequiredMixin, CreateView):
+    """
+    Display the page to create a team for new users.
+    """
+
     model = Team
     form_class = TeamForm
     extra_context = dict(title=_("Create team"))
@@ -43,14 +47,24 @@ class CreateTeamView(LoginRequiredMixin, CreateView):
 
     @transaction.atomic
     def form_valid(self, form):
+        """
+        When a team is about to be created, the user automatically
+        joins the team, a mailing list got created and the user is
+        automatically subscribed to this mailing list, and finally
+        a Matrix room is created and the user is invited in this room.
+        """
         ret = super().form_valid(form)
+        # The user joins the team
         user = self.request.user
         registration = user.registration
         registration.team = form.instance
         registration.save()
+
+        # Subscribe the user mail address to the team mailing list
         get_sympa_client().subscribe(user.email, f"equipe-{form.instance.trigram.lower()}", False,
                                      f"{user.first_name} {user.last_name}")
 
+        # Invite the user in the team Matrix room
         Matrix.invite(f"#team-{form.instance.trigram.lower()}:correspondances-maths.fr",
                       f"@{user.registration.matrix_username}:correspondances-maths.fr")
         return ret
@@ -60,6 +74,9 @@ class CreateTeamView(LoginRequiredMixin, CreateView):
 
 
 class JoinTeamView(LoginRequiredMixin, FormView):
+    """
+    Participants can join a team with the access code of the team.
+    """
     model = Team
     form_class = JoinTeamForm
     extra_context = dict(title=_("Join team"))
@@ -76,15 +93,24 @@ class JoinTeamView(LoginRequiredMixin, FormView):
 
     @transaction.atomic
     def form_valid(self, form):
+        """
+        When a user joins a team, the user is automatically subscribed to
+        the team mailing list,the user is invited in the team Matrix room.
+        """
         self.object = form.instance
         ret = super().form_valid(form)
+
+        # Join the team
         user = self.request.user
         registration = user.registration
         registration.team = form.instance
         registration.save()
+
+        # Subscribe to the team mailing list
         get_sympa_client().subscribe(user.email, f"equipe-{form.instance.trigram.lower()}", False,
                                      f"{user.first_name} {user.last_name}")
 
+        # Invite the user in the team Matrix room
         Matrix.invite(f"#team-{form.instance.trigram.lower()}:correspondances-maths.fr",
                       f"@{user.registration.matrix_username}:correspondances-maths.fr")
         return ret
@@ -94,6 +120,10 @@ class JoinTeamView(LoginRequiredMixin, FormView):
 
 
 class MyTeamDetailView(LoginRequiredMixin, RedirectView):
+    """
+    Redirect to the detail of the team in which the user is.
+    """
+
     def get_redirect_url(self, *args, **kwargs):
         user = self.request.user
         registration = user.registration
@@ -105,11 +135,15 @@ class MyTeamDetailView(LoginRequiredMixin, RedirectView):
 
 
 class TeamDetailView(LoginRequiredMixin, FormMixin, ProcessFormView, DetailView):
+    """
+    Display the detail of a team.
+    """
     model = Team
 
     def get(self, request, *args, **kwargs):
         user = request.user
         self.object = self.get_object()
+        # Ensure that the user is an admin or a member of the team
         if user.registration.is_admin or user.registration.participates and user.registration.team.pk == kwargs["pk"]:
             return super().get(request, *args, **kwargs)
         raise PermissionDenied
@@ -120,6 +154,8 @@ class TeamDetailView(LoginRequiredMixin, FormMixin, ProcessFormView, DetailView)
         team = self.get_object()
         context["request_validation_form"] = RequestValidationForm(self.request.POST or None)
         context["validation_form"] = ValidateParticipationForm(self.request.POST or None)
+        # A team is complete when there are at least 3 members that have sent their photo authorization
+        # and confirmed their email address
         context["can_validate"] = team.students.count() >= 3 and \
             all(r.email_confirmed for r in team.students.all()) and \
             all(r.photo_authorization for r in team.students.all()) and \
@@ -188,6 +224,9 @@ class TeamDetailView(LoginRequiredMixin, FormMixin, ProcessFormView, DetailView)
 
 
 class TeamUpdateView(LoginRequiredMixin, UpdateView):
+    """
+    Update the detail of a team
+    """
     model = Team
     form_class = TeamForm
     template_name = "participation/update_team.html"
@@ -218,6 +257,9 @@ class TeamUpdateView(LoginRequiredMixin, UpdateView):
 
 
 class TeamAuthorizationsView(LoginRequiredMixin, DetailView):
+    """
+    Get as a ZIP archive all the authorizations that are sent
+    """
     model = Team
 
     def dispatch(self, request, *args, **kwargs):
@@ -245,6 +287,10 @@ class TeamAuthorizationsView(LoginRequiredMixin, DetailView):
 
 
 class TeamLeaveView(LoginRequiredMixin, TemplateView):
+    """
+    A team member leaves a team
+    """
+
     template_name = "participation/team_leave.html"
 
     def dispatch(self, request, *args, **kwargs):
@@ -258,6 +304,10 @@ class TeamLeaveView(LoginRequiredMixin, TemplateView):
 
     @transaction.atomic()
     def post(self, request, *args, **kwargs):
+        """
+        When the team is left, the user is unsubscribed from the team mailing list
+        and kicked from the team room.
+        """
         team = request.user.registration.team
         request.user.registration.team = None
         request.user.registration.save()
@@ -271,6 +321,9 @@ class TeamLeaveView(LoginRequiredMixin, TemplateView):
 
 
 class MyParticipationDetailView(LoginRequiredMixin, RedirectView):
+    """
+    Redirects to the detail view of the participation of the team.
+    """
     def get_redirect_url(self, *args, **kwargs):
         user = self.request.user
         registration = user.registration
@@ -282,6 +335,9 @@ class MyParticipationDetailView(LoginRequiredMixin, RedirectView):
 
 
 class ParticipationDetailView(LoginRequiredMixin, DetailView):
+    """
+    Display detail about the participation of a team, and manage the video submission.
+    """
     model = Participation
 
     def dispatch(self, request, *args, **kwargs):
@@ -303,6 +359,9 @@ class ParticipationDetailView(LoginRequiredMixin, DetailView):
 
 
 class UploadVideoView(LoginRequiredMixin, UpdateView):
+    """
+    Upload a solution video for a team.
+    """
     model = Video
     form_class = UploadVideoForm
     template_name = "participation/upload_video.html"
@@ -319,11 +378,17 @@ class UploadVideoView(LoginRequiredMixin, UpdateView):
 
 
 class CalendarView(SingleTableView):
+    """
+    Display the calendar of the action.
+    """
     table_class = CalendarTable
     model = Phase
 
 
 class PhaseUpdateView(AdminMixin, UpdateView):
+    """
+    Update a phase of the calendar, if we have sufficient rights.
+    """
     model = Phase
     form_class = PhaseForm
 
diff --git a/apps/registration/apps.py b/apps/registration/apps.py
index 3bf6fa5..7b1e19d 100644
--- a/apps/registration/apps.py
+++ b/apps/registration/apps.py
@@ -3,6 +3,9 @@ from django.db.models.signals import post_save, pre_save
 
 
 class RegistrationConfig(AppConfig):
+    """
+    Registration app contains the detail about users only.
+    """
     name = 'registration'
 
     def ready(self):
diff --git a/apps/registration/forms.py b/apps/registration/forms.py
index 75a25e3..18d76eb 100644
--- a/apps/registration/forms.py
+++ b/apps/registration/forms.py
@@ -9,6 +9,11 @@ from .models import AdminRegistration, CoachRegistration, StudentRegistration
 
 
 class SignupForm(UserCreationForm):
+    """
+    Signup form to registers participants and coaches
+    They can choose the role at the registration.
+    """
+
     role = forms.ChoiceField(
         label=lambda: _("role").capitalize(),
         choices=lambda: [
@@ -29,6 +34,10 @@ class SignupForm(UserCreationForm):
 
 
 class UserForm(forms.ModelForm):
+    """
+    Replace the default user form to require the first name, last name and the email.
+    The username is always equal to the email.
+    """
     def __init__(self, *args, **kwargs):
         super().__init__(*args, **kwargs)
         self.fields["first_name"].required = True
@@ -41,12 +50,18 @@ class UserForm(forms.ModelForm):
 
 
 class StudentRegistrationForm(forms.ModelForm):
+    """
+    A student can update its class, its school and if it allows Animath to contact him/her later.
+    """
     class Meta:
         model = StudentRegistration
         fields = ('student_class', 'school', 'give_contact_to_animath',)
 
 
 class PhotoAuthorizationForm(forms.ModelForm):
+    """
+    Form to send a photo authorization.
+    """
     def clean_photo_authorization(self):
         file = self.files["photo_authorization"]
         if file.content_type not in ["application/pdf", "image/png", "image/jpeg"]:
@@ -63,12 +78,18 @@ class PhotoAuthorizationForm(forms.ModelForm):
 
 
 class CoachRegistrationForm(forms.ModelForm):
+    """
+    A coach can tell its professional activity.
+    """
     class Meta:
         model = CoachRegistration
         fields = ('professional_activity', 'give_contact_to_animath',)
 
 
 class AdminRegistrationForm(forms.ModelForm):
+    """
+    Admins can tell everything they want.
+    """
     class Meta:
         model = AdminRegistration
         fields = ('role', 'give_contact_to_animath',)
diff --git a/apps/registration/models.py b/apps/registration/models.py
index de33c65..7fe7292 100644
--- a/apps/registration/models.py
+++ b/apps/registration/models.py
@@ -11,6 +11,11 @@ from polymorphic.models import PolymorphicModel
 
 
 class Registration(PolymorphicModel):
+    """
+    Registrations store extra content that are not asked in the User Model.
+    This is specific to the role of the user, see StudentRegistration,
+    ClassRegistration or AdminRegistration..
+    """
     user = models.OneToOneField(
         "auth.User",
         on_delete=models.CASCADE,
@@ -28,6 +33,10 @@ class Registration(PolymorphicModel):
     )
 
     def send_email_validation_link(self):
+        """
+        The account got created or the email got changed.
+        Send an email that contains a link to validate the address.
+        """
         subject = "[Corres2math] " + str(_("Activate your Correspondances account"))
         token = email_validation_token.make_token(self.user)
         uid = urlsafe_base64_encode(force_bytes(self.user.pk))
@@ -84,6 +93,10 @@ def get_random_filename(instance, filename):
 
 
 class StudentRegistration(Registration):
+    """
+    Specific registration for students.
+    They have a team, a student class and a school.
+    """
     team = models.ForeignKey(
         "participation.Team",
         related_name="students",
@@ -129,6 +142,10 @@ class StudentRegistration(Registration):
 
 
 class CoachRegistration(Registration):
+    """
+    Specific registration for coaches.
+    They have a team and a professional activity.
+    """
     team = models.ForeignKey(
         "participation.Team",
         related_name="coachs",
@@ -157,6 +174,10 @@ class CoachRegistration(Registration):
 
 
 class AdminRegistration(Registration):
+    """
+    Specific registration for admins.
+    They have a field to justify they status.
+    """
     role = models.TextField(
         verbose_name=_("role of the administrator"),
     )
diff --git a/apps/registration/search_indexes.py b/apps/registration/search_indexes.py
index b04b0b9..d52ce87 100644
--- a/apps/registration/search_indexes.py
+++ b/apps/registration/search_indexes.py
@@ -4,6 +4,9 @@ from .models import Registration
 
 
 class RegistrationIndex(indexes.ModelSearchIndex, indexes.Indexable):
+    """
+    Registrations are indexed by the user detail.
+    """
     text = indexes.NgramField(document=True, use_template=True)
 
     class Meta:
diff --git a/apps/registration/signals.py b/apps/registration/signals.py
index 042ad06..57d440a 100644
--- a/apps/registration/signals.py
+++ b/apps/registration/signals.py
@@ -5,10 +5,17 @@ from .models import AdminRegistration, Registration
 
 
 def set_username(instance, **_):
+    """
+    Ensure that the user username is always equal to the user email address.
+    """
     instance.username = instance.email
 
 
 def send_email_link(instance, **_):
+    """
+    If the email address got changed, send a new validation link
+     and update the registration status in the team mailing list.
+    """
     if instance.pk:
         old_instance = User.objects.get(pk=instance.pk)
         if old_instance.email != instance.email:
@@ -25,5 +32,9 @@ def send_email_link(instance, **_):
 
 
 def create_admin_registration(instance, **_):
+    """
+    When a super user got created through console,
+    ensure that an admin registration is created.
+    """
     if instance.is_superuser:
         AdminRegistration.objects.get_or_create(user=instance)
diff --git a/apps/registration/tables.py b/apps/registration/tables.py
index bc617a9..7995ade 100644
--- a/apps/registration/tables.py
+++ b/apps/registration/tables.py
@@ -5,6 +5,9 @@ from .models import Registration
 
 
 class RegistrationTable(tables.Table):
+    """
+    Table of all registrations.
+    """
     last_name = tables.LinkColumn(
         'registration:user_detail',
         args=[tables.A("user_id")],
diff --git a/apps/registration/tests.py b/apps/registration/tests.py
index 8286565..18e5ff4 100644
--- a/apps/registration/tests.py
+++ b/apps/registration/tests.py
@@ -10,6 +10,9 @@ from .models import CoachRegistration, Registration, StudentRegistration
 
 class TestIndexPage(TestCase):
     def test_index(self) -> None:
+        """
+        Display the index page, without any right.
+        """
         response = self.client.get(reverse("index"))
         self.assertEqual(response.status_code, 200)
 
@@ -29,6 +32,9 @@ class TestRegistration(TestCase):
         CoachRegistration.objects.create(user=self.coach, professional_activity="Teacher")
 
     def test_admin_pages(self):
+        """
+        Check that admin pages are rendering successfully.
+        """
         response = self.client.get(reverse("admin:index") + "registration/registration/")
         self.assertEqual(response.status_code, 200)
 
@@ -45,6 +51,9 @@ class TestRegistration(TestCase):
         self.assertEqual(response.status_code, 200)
 
     def test_registration(self):
+        """
+        Ensure that the signup form is working successfully.
+        """
         response = self.client.get(reverse("registration:signup"))
         self.assertEqual(response.status_code, 200)
 
@@ -109,6 +118,9 @@ class TestRegistration(TestCase):
         self.assertRedirects(response, reverse("registration:email_validation_sent"), 302, 200)
 
     def test_login(self):
+        """
+        With a registered user, try to log in
+        """
         response = self.client.get(reverse("login"))
         self.assertEqual(response.status_code, 200)
 
@@ -127,6 +139,9 @@ class TestRegistration(TestCase):
         self.assertRedirects(response, reverse("index"), 302, 200)
 
     def test_user_detail(self):
+        """
+        Load a user detail page.
+        """
         response = self.client.get(reverse("registration:my_account_detail"))
         self.assertRedirects(response, reverse("registration:user_detail", args=(self.user.pk,)))
 
@@ -134,6 +149,9 @@ class TestRegistration(TestCase):
         self.assertEqual(response.status_code, 200)
 
     def test_update_user(self):
+        """
+        Update the user information, for each type of user.
+        """
         for user, data in [(self.user, dict(role="Bot")),
                            (self.student, dict(student_class=11, school="Sky")),
                            (self.coach, dict(professional_activity="God"))]:
@@ -162,6 +180,9 @@ class TestRegistration(TestCase):
             self.assertEqual(user.first_name, "Changed")
 
     def test_upload_photo_authorization(self):
+        """
+        Try to upload a photo authorization.
+        """
         response = self.client.get(reverse("registration:upload_user_photo_authorization",
                                            args=(self.student.registration.pk,)))
         self.assertEqual(response.status_code, 200)
diff --git a/apps/registration/views.py b/apps/registration/views.py
index a29b9a8..4626d31 100644
--- a/apps/registration/views.py
+++ b/apps/registration/views.py
@@ -19,6 +19,9 @@ from .models import StudentRegistration
 
 
 class SignupView(CreateView):
+    """
+    Signup, as a participant or a coach.
+    """
     model = User
     form_class = SignupForm
     template_name = "registration/signup.html"
@@ -126,23 +129,34 @@ class UserResendValidationEmailView(LoginRequiredMixin, DetailView):
 
 
 class MyAccountDetailView(LoginRequiredMixin, RedirectView):
+    """
+    Redirect to our own profile detail page.
+    """
     def get_redirect_url(self, *args, **kwargs):
         return reverse_lazy("registration:user_detail", args=(self.request.user.pk,))
 
 
 class UserDetailView(LoginRequiredMixin, DetailView):
+    """
+    Display the detail about a user.
+    """
+
     model = User
     context_object_name = "user_object"
     template_name = "registration/user_detail.html"
 
     def dispatch(self, request, *args, **kwargs):
         user = request.user
+        # Only an admin or the concerned user can see the information
         if not user.registration.is_admin and user.pk != kwargs["pk"]:
             raise PermissionDenied
         return super().dispatch(request, *args, **kwargs)
 
 
 class UserUpdateView(LoginRequiredMixin, UpdateView):
+    """
+    Update the detail about a user and its registration.
+    """
     model = User
     form_class = UserForm
     template_name = "registration/update_user.html"
@@ -176,6 +190,9 @@ class UserUpdateView(LoginRequiredMixin, UpdateView):
 
 
 class UserUploadPhotoAuthorizationView(LoginRequiredMixin, UpdateView):
+    """
+    A participant can send its photo authorization.
+    """
     model = StudentRegistration
     form_class = PhotoAuthorizationForm
     template_name = "registration/upload_photo_authorization.html"
@@ -198,6 +215,9 @@ class UserUploadPhotoAuthorizationView(LoginRequiredMixin, UpdateView):
 
 
 class PhotoAuthorizationView(LoginRequiredMixin, View):
+    """
+    Display the sent photo authorization.
+    """
     def get(self, request, *args, **kwargs):
         filename = kwargs["filename"]
         path = f"media/authorization/photo/{filename}"
@@ -207,18 +227,21 @@ class PhotoAuthorizationView(LoginRequiredMixin, View):
         user = request.user
         if not user.registration.is_admin and user.pk != student.user.pk:
             raise PermissionDenied
+        # Guess mime type of the file
         mime = Magic(mime=True)
         mime_type = mime.from_file(path)
         ext = mime_type.split("/")[1].replace("jpeg", "jpg")
+        # Replace file name
         true_file_name = _("Photo authorization of {student}.{ext}").format(student=str(student), ext=ext)
         return FileResponse(open(path, "rb"), content_type=mime_type, filename=true_file_name)
 
 
 class UserImpersonateView(LoginRequiredMixin, RedirectView):
+    """
+    An administrator can log in through this page as someone else, and act as this other person.
+    """
+
     def dispatch(self, request, *args, **kwargs):
-        """
-        An administrator can log in through this page as someone else, and act as this other person.
-        """
         if self.request.user.registration.is_admin:
             if not User.objects.filter(pk=kwargs["pk"]).exists():
                 raise Http404
diff --git a/corres2math/matrix.py b/corres2math/matrix.py
index 784c905..cb1e0e6 100644
--- a/corres2math/matrix.py
+++ b/corres2math/matrix.py
@@ -6,11 +6,23 @@ from nio import *
 
 
 class Matrix:
+    """
+    Utility class to manage interaction with the Matrix homeserver.
+    This log in the @corres2mathbot account (must be created before).
+    The access token is then stored.
+    All is done with this bot account, that is a server administrator.
+    Tasks are normally asynchronous, but for compatibility we make
+    them synchronous.
+    """
     _token: str = None
     _device_id: str = None
 
     @classmethod
     async def _get_client(cls) -> AsyncClient:
+        """
+        Retrieve the bot account.
+        If not logged, log in and store access token.
+        """
         client = AsyncClient("https://correspondances-maths.fr", "@corres2mathbot:correspondances-maths.fr")
         client.user_id = "@corres2mathbot:correspondances-maths.fr"
 
@@ -35,12 +47,18 @@ class Matrix:
     @classmethod
     @async_to_sync
     async def set_display_name(cls, name: str) -> Union[ProfileSetDisplayNameResponse, ProfileSetDisplayNameError]:
+        """
+        Set the display name of the bot account.
+        """
         client = await cls._get_client()
         return await client.set_displayname(name)
 
     @classmethod
     @async_to_sync
     async def set_avatar(cls, avatar_url: str) -> Union[ProfileSetAvatarResponse, ProfileSetAvatarError]:
+        """
+        Set the display avatar of the bot account.
+        """
         client = await cls._get_client()
         return await client.set_avatar(avatar_url)
 
@@ -55,6 +73,58 @@ class Matrix:
             monitor: Optional[TransferMonitor] = None,
             filesize: Optional[int] = None,
     ) -> Tuple[Union[UploadResponse, UploadError], Optional[Dict[str, Any]]]:
+        """
+        Upload a file to the content repository.
+
+        Returns a tuple containing:
+
+        - Either a `UploadResponse` if the request was successful, or a
+          `UploadError` if there was an error with the request
+
+        - A dict with file decryption info if encrypt is ``True``,
+          else ``None``.
+        Args:
+            data_provider (Callable, SynchronousFile, AsyncFile): A function
+                returning the data to upload or a file object. File objects
+                must be opened in binary mode (``mode="r+b"``). Callables
+                returning a path string, Path, async iterable or aiofiles
+                open binary file object allow the file data to be read in an
+                asynchronous and lazy way (without reading the entire file
+                into memory). Returning a synchronous iterable or standard
+                open binary file object will still allow the data to be read
+                lazily, but not asynchronously.
+
+                The function will be called again if the upload fails
+                due to a server timeout, in which case it must restart
+                from the beginning.
+                Callables receive two arguments: the total number of
+                429 "Too many request" errors that occured, and the total
+                number of server timeout exceptions that occured, thus
+                cleanup operations can be performed for retries if necessary.
+
+            content_type (str): The content MIME type of the file,
+                e.g. "image/png".
+                Defaults to "application/octet-stream", corresponding to a
+                generic binary file.
+                Custom values are ignored if encrypt is ``True``.
+
+            filename (str, optional): The file's original name.
+
+            encrypt (bool): If the file's content should be encrypted,
+                necessary for files that will be sent to encrypted rooms.
+                Defaults to ``False``.
+
+            monitor (TransferMonitor, optional): If a ``TransferMonitor``
+                object is passed, it will be updated by this function while
+                uploading.
+                From this object, statistics such as currently
+                transferred bytes or estimated remaining time can be gathered
+                while the upload is running as a task; it also allows
+                for pausing and cancelling.
+
+            filesize (int, optional): Size in bytes for the file to transfer.
+                If left as ``None``, some servers might refuse the upload.
+        """
         client = await cls._get_client()
         return await client.upload(data_provider, content_type, filename, encrypt, monitor, filesize)
 
@@ -74,6 +144,61 @@ class Matrix:
             initial_state=(),
             power_level_override: Optional[Dict[str, Any]] = None,
     ) -> Union[RoomCreateResponse, RoomCreateError]:
+        """
+        Create a new room.
+
+        Returns either a `RoomCreateResponse` if the request was successful or
+        a `RoomCreateError` if there was an error with the request.
+
+        Args:
+            visibility (RoomVisibility): whether to have the room published in
+                the server's room directory or not.
+                Defaults to ``RoomVisibility.private``.
+
+            alias (str, optional): The desired canonical alias local part.
+                For example, if set to "foo" and the room is created on the
+                "example.com" server, the room alias will be
+                "#foo:example.com".
+
+            name (str, optional): A name to set for the room.
+
+            topic (str, optional): A topic to set for the room.
+
+            room_version (str, optional): The room version to set.
+                If not specified, the homeserver will use its default setting.
+                If a version not supported by the homeserver is specified,
+                a 400 ``M_UNSUPPORTED_ROOM_VERSION`` error will be returned.
+
+            federate (bool): Whether to allow users from other homeservers from
+                joining the room. Defaults to ``True``.
+                Cannot be changed later.
+
+            is_direct (bool): If this should be considered a
+                direct messaging room.
+                If ``True``, the server will set the ``is_direct`` flag on
+                ``m.room.member events`` sent to the users in ``invite``.
+                Defaults to ``False``.
+
+            preset (RoomPreset, optional): The selected preset will set various
+                rules for the room.
+                If unspecified, the server will choose a preset from the
+                ``visibility``: ``RoomVisibility.public`` equates to
+                ``RoomPreset.public_chat``, and
+                ``RoomVisibility.private`` equates to a
+                ``RoomPreset.private_chat``.
+
+            invite (list): A list of user id to invite to the room.
+
+            initial_state (list): A list of state event dicts to send when
+                the room is created.
+                For example, a room could be made encrypted immediatly by
+                having a ``m.room.encryption`` event dict.
+
+            power_level_override (dict): A ``m.room.power_levels content`` dict
+                to override the default.
+                The dict will be applied on top of the generated
+                ``m.room.power_levels`` event before it is sent to the room.
+        """
         client = await cls._get_client()
         return await client.room_create(
             visibility, alias, name, topic, room_version, federate, is_direct, preset, invite, initial_state,
@@ -81,6 +206,10 @@ class Matrix:
 
     @classmethod
     async def resolve_room_alias(cls, room_alias: str) -> Optional[str]:
+        """
+        Resolve a room alias to a room ID.
+        Return None if the alias does not exist.
+        """
         client = await cls._get_client()
         resp: RoomResolveAliasResponse = await client.room_resolve_alias(room_alias)
         if isinstance(resp, RoomResolveAliasError):
@@ -90,6 +219,17 @@ class Matrix:
     @classmethod
     @async_to_sync
     async def invite(cls, room_id: str, user_id: str) -> Union[RoomInviteResponse, RoomInviteError]:
+        """
+        Invite a user to a room.
+
+        Returns either a `RoomInviteResponse` if the request was successful or
+        a `RoomInviteError` if there was an error with the request.
+
+        Args:
+            room_id (str): The room id of the room that the user will be
+                invited to.
+            user_id (str): The user id of the user that should be invited.
+        """
         client = await cls._get_client()
         if room_id.startswith("#"):
             room_id = await cls.resolve_room_alias(room_id)
@@ -98,6 +238,21 @@ class Matrix:
     @classmethod
     @async_to_sync
     async def kick(cls, room_id: str, user_id: str, reason: str = None) -> Union[RoomKickResponse, RoomInviteError]:
+        """
+        Kick a user from a room, or withdraw their invitation.
+
+        Kicking a user adjusts their membership to "leave" with an optional
+        reason.
+
+        Returns either a `RoomKickResponse` if the request was successful or
+        a `RoomKickError` if there was an error with the request.
+
+        Args:
+            room_id (str): The room id of the room that the user will be
+                kicked from.
+            user_id (str): The user_id of the user that should be kicked.
+            reason (str, optional): A reason for which the user is kicked.
+        """
         client = await cls._get_client()
         if room_id.startswith("#"):
             room_id = await cls.resolve_room_alias(room_id)
@@ -107,6 +262,19 @@ class Matrix:
     @async_to_sync
     async def set_room_power_level(cls, room_id: str, user_id: str, power_level: int)\
             -> Union[RoomPutStateResponse, RoomPutStateError]:
+        """
+        Put a given power level to a user in a certain room.
+
+        Returns either a `RoomPutStateResponse` if the request was successful or
+        a `RoomPutStateError` if there was an error with the request.
+
+        Args:
+            room_id (str): The room id of the room where the power level
+                of the user should be updated.
+            user_id (str): The user_id of the user which power level should
+                be updated.
+            power_level (int): The target power level to give.
+        """
         client = await cls._get_client()
         if room_id.startswith("#"):
             room_id = await cls.resolve_room_alias(room_id)
@@ -119,6 +287,20 @@ class Matrix:
     @async_to_sync
     async def set_room_power_level_event(cls, room_id: str, event: str, power_level: int)\
             -> Union[RoomPutStateResponse, RoomPutStateError]:
+        """
+        Define the minimal power level to have to send a certain event type
+         in a given room.
+
+        Returns either a `RoomPutStateResponse` if the request was successful or
+        a `RoomPutStateError` if there was an error with the request.
+
+        Args:
+            room_id (str): The room id of the room where the power level
+                of the event should be updated.
+            event (str): The event name which minimal power level should
+                be updated.
+            power_level (int): The target power level to give.
+        """
         client = await cls._get_client()
         if room_id.startswith("#"):
             room_id = await cls.resolve_room_alias(room_id)
@@ -134,7 +316,19 @@ class Matrix:
     @async_to_sync
     async def set_room_avatar(cls, room_id: str, avatar_uri: str)\
             -> Union[RoomPutStateResponse, RoomPutStateError]:
+        """
+        Define the avatar of a room.
+
+        Returns either a `RoomPutStateResponse` if the request was successful or
+        a `RoomPutStateError` if there was an error with the request.
+
+        Args:
+            room_id (str): The room id of the room where the avatar
+                should be changed.
+            avatar_uri (str): The internal avatar URI to apply.
+        """
         client = await cls._get_client()
+        client
         if room_id.startswith("#"):
             room_id = await cls.resolve_room_alias(room_id)
         return await client.room_put_state(room_id, "m.room.avatar", content={