diff --git a/accounts/decorators.py b/accounts/decorators.py
index fb769de..3e88d72 100644
--- a/accounts/decorators.py
+++ b/accounts/decorators.py
@@ -1,15 +1,16 @@
 from functools import wraps
+
 from django.core.exceptions import PermissionDenied
 
 from accounts.utils import is_orga, is_staff
 
 
-def orga_required(func):
+def orga_required(view_func):
     def _is_orga(request, *args, **kwargs):
         if is_orga(request, request.user):
             return view_func(request, *args, **kwargs)
         raise PermissionDenied
-    return wraps(func)(_is_orga)
+    return wraps(view_func)(_is_orga)
 
 
 def staff_required(view_func):
diff --git a/accounts/forms.py b/accounts/forms.py
index c523106..926ee7a 100644
--- a/accounts/forms.py
+++ b/accounts/forms.py
@@ -1,26 +1,28 @@
+from django import forms
 from django.contrib.auth.models import User
 from django.forms.models import modelform_factory
-from django import forms
 
-from django_select2.forms import Select2Widget, Select2MultipleWidget
+from django_select2.forms import Select2Widget
 
 from .models import Participation, Profile
 
-__all__ = ['UserForm', 'ProfileForm', 'ProfileOrgaForm', 'ParticipationOrgaForm']
-
-
 UserForm = modelform_factory(User, fields=['first_name', 'last_name', 'email', 'username'])
 
 ProfileForm = modelform_factory(Profile, fields=['biography'])
 
-ParticipationForm = modelform_factory(Participation, fields=['transport', 'connector', 'sound', 'videotaped', 'video_licence', 'constraints'],
-                                                     widgets={'transport': forms.CheckboxSelectMultiple(), 'connector': forms.CheckboxSelectMultiple()})
+ParticipationForm = modelform_factory(Participation, fields=['transport', 'connector', 'sound', 'videotaped',
+                                                             'video_licence', 'constraints'],
+                                      widgets={'transport': forms.CheckboxSelectMultiple(),
+                                               'connector': forms.CheckboxSelectMultiple()})
 
 ProfileOrgaForm = modelform_factory(Profile, fields=['biography', 'notes'])
 
 ParticipationOrgaForm = modelform_factory(Participation,
-                                          fields=['transport', 'connector', 'sound', 'videotaped', 'video_licence', 'constraints', 'orga'],
-                                          widgets={'transport': forms.CheckboxSelectMultiple(), 'connector': forms.CheckboxSelectMultiple()})
+                                          fields=['transport', 'connector', 'sound', 'videotaped', 'video_licence',
+                                                  'constraints', 'orga'],
+                                          widgets={'transport': forms.CheckboxSelectMultiple(),
+                                                   'connector': forms.CheckboxSelectMultiple()})
+
 
 class ParticipationField(forms.ModelChoiceField):
     def label_from_instance(self, obj):
@@ -29,4 +31,5 @@ class ParticipationField(forms.ModelChoiceField):
 
 class NewParticipationForm(forms.Form):
 
-    participant = ParticipationField(User.objects.all(), widget=Select2Widget(), label='Add participant from existing account')
+    participant = ParticipationField(User.objects.all(), widget=Select2Widget(),
+                                     label='Add participant from existing account')
diff --git a/accounts/models.py b/accounts/models.py
index 95607f1..f2eef40 100644
--- a/accounts/models.py
+++ b/accounts/models.py
@@ -9,8 +9,6 @@ from ponyconf.utils import PonyConfModel, enum_to_choices
 
 from .utils import generate_user_uid
 
-__all__ = ['Profile']
-
 
 class Profile(PonyConfModel):
 
@@ -46,8 +44,6 @@ class Connector(Option):
 
 class Participation(PonyConfModel):
 
-    TRANSPORTS = IntEnum('Transport', 'train plane others')
-    CONNECTORS = IntEnum('Connector', 'VGA HDMI miniDP')
     LICENCES = IntEnum('Video licence', 'CC-Zero CC-BY CC-BY-SA CC-BY-ND CC-BY-NC CC-BY-NC-SA CC-BY-NC-ND')
 
     site = models.ForeignKey(Site, on_delete=models.CASCADE)
@@ -78,8 +74,3 @@ class Participation(PonyConfModel):
 
     def is_staff(self):
         return self.is_orga() or self.user.topic_set.exists()
-
-    @property
-    def reviewed_topics(self):
-        from proposals.models import Topic
-        return Topic.objects.filter(reviewers=self.user).all()
diff --git a/accounts/signals.py b/accounts/signals.py
index 666c703..0e3eab5 100644
--- a/accounts/signals.py
+++ b/accounts/signals.py
@@ -5,7 +5,7 @@ from django.contrib.sites.shortcuts import get_current_site
 from django.db.models.signals import post_save
 from django.dispatch import receiver
 
-from .models import Participation, Profile, Transport, Connector
+from .models import Connector, Participation, Profile, Transport
 
 
 def create_default_options(sender, **kwargs):
diff --git a/accounts/templates/accounts/participation_list.html b/accounts/templates/accounts/participation_list.html
index 9f4198d..aba6801 100644
--- a/accounts/templates/accounts/participation_list.html
+++ b/accounts/templates/accounts/participation_list.html
@@ -26,7 +26,7 @@
     <td><a href="{{ participation.get_absolute_url }}">{{ participation.user.username }}</a></td>
     <td>{{ participation.user.get_full_name }}</td>
     <td>{{ participation.is_orga|yesno:"✔,✘" }}</td>
-    <td>{% for topic in participation.reviewed_topics %}{{ topic.get_link }}{% if not forloop.last %},
+    <td>{% for topic in participation.user.topic_set.all %}{{ topic.get_link }}{% if not forloop.last %},
       {% endif %}{% endfor %}</td>
     <td>
       <a href="{% url 'conversation' participation.user.username %}" data-toggle="tooltip" data-placement="bottom"
diff --git a/accounts/tests.py b/accounts/tests.py
index 685c408..ba50f10 100644
--- a/accounts/tests.py
+++ b/accounts/tests.py
@@ -32,10 +32,12 @@ class AccountTests(TestCase):
         self.client.login(username='b', password='b')
 
         # He tries with an invalid address
-        self.client.post(reverse('profile'), {'email': 'bnewdomain.com', 'username': 'z', 'biography': 'tester', 'video_licence': 1})
+        self.client.post(reverse('profile'), {'email': 'bnewdomain.com', 'username': 'z', 'biography': 'tester',
+                                              'video_licence': 1})
         self.assertEqual(User.objects.filter(username='z').count(), 0)
 
-        self.client.post(reverse('profile'), {'email': 'b@newdomain.com', 'username': 'z', 'biography': 'tester', 'video_licence': 1})
+        self.client.post(reverse('profile'), {'email': 'b@newdomain.com', 'username': 'z', 'biography': 'tester',
+                                              'video_licence': 1})
 
         user = User.objects.get(username='z')
         self.assertEqual(user.email, 'b@newdomain.com')
diff --git a/accounts/views.py b/accounts/views.py
index b3d1340..4cb0528 100644
--- a/accounts/views.py
+++ b/accounts/views.py
@@ -1,20 +1,17 @@
 from django.contrib import messages
 from django.contrib.auth.decorators import login_required
-from django.core.exceptions import PermissionDenied
-from django.shortcuts import get_object_or_404, render, redirect
-from django.views.generic import ListView
 from django.contrib.sites.shortcuts import get_current_site
-from django.core.urlresolvers import reverse
 from django.core.exceptions import PermissionDenied
+from django.core.urlresolvers import reverse
+from django.shortcuts import get_object_or_404, redirect, render
 
 from registration.backends.default.views import RegistrationView
 
-from .forms import ParticipationForm, ParticipationOrgaForm, ProfileForm, ProfileOrgaForm, UserForm, NewParticipationForm
-from .mixins import StaffRequiredMixin
 from .decorators import staff_required
-from .models import Participation, Profile
+from .forms import (NewParticipationForm, ParticipationForm,
+                    ParticipationOrgaForm, ProfileForm, ProfileOrgaForm, UserForm)
+from .models import Participation, Profile, User
 from .utils import can_edit_profile, is_orga
-from .models import User
 
 RESET_PASSWORD_BUTTON = ('password_reset', 'warning', 'Reset your password')
 CHANGE_PASSWORD_BUTTON = ('password_change', 'warning', 'Change password')
@@ -30,7 +27,8 @@ def profile(request):
 
     forms = [UserForm(request.POST or None, instance=request.user),
              ProfileForm(request.POST or None, instance=request.user.profile),
-             ParticipationForm(request.POST or None, instance=Participation.objects.get(site=get_current_site(request), user=request.user))]
+             ParticipationForm(request.POST or None, instance=Participation.objects.get(site=get_current_site(request),
+                                                                                        user=request.user))]
 
     if request.method == 'POST':
         if all(form.is_valid() for form in forms):
@@ -72,10 +70,11 @@ def edit(request, username):
     if not can_edit_profile(request, profile):
         raise PermissionDenied()
 
-    participation_form_class = ParticipationOrgaForm if is_orga(request, request.user) else ParticipationForm
+    participation_form = ParticipationOrgaForm if is_orga(request, request.user) else ParticipationForm
     forms = [UserForm(request.POST or None, instance=profile.user),
              ProfileOrgaForm(request.POST or None, instance=profile),
-             participation_form_class(request.POST or None, instance=Participation.objects.get(site=get_current_site(request), user=profile.user))]
+             participation_form(request.POST or None,
+                                instance=Participation.objects.get(site=get_current_site(request), user=profile.user))]
 
     if request.method == 'POST':
         if all(form.is_valid() for form in forms):
diff --git a/conversations/forms.py b/conversations/forms.py
index d263b9f..f84879c 100644
--- a/conversations/forms.py
+++ b/conversations/forms.py
@@ -2,5 +2,4 @@ from django.forms.models import modelform_factory
 
 from .models import Message
 
-MessageForm = modelform_factory(Message,
-                                fields=['content'])
+MessageForm = modelform_factory(Message, fields=['content'])
diff --git a/conversations/post-mail.sh b/conversations/post-mail.sh
index 03f0725..edf3154 100755
--- a/conversations/post-mail.sh
+++ b/conversations/post-mail.sh
@@ -4,7 +4,7 @@
 # Get the value of REPLY_KEY from the django setting.
 
 # Postfix users can set up an alias file with this content:
-# reply: "|/path/to/post-mail.sh mykey@https://example.org/conversations/recv/ 
-# don't forget to run postalias and to add the alias file to main.cf under alias_map. 
+# reply: "|/path/to/post-mail.sh mykey@https://example.org/conversations/recv/
+# don't forget to run postalias and to add the alias file to main.cf under alias_map.
 
 curl ${@#*\@} -F key=${@%\@*} -F "email=@-"
diff --git a/conversations/sieve-filter b/conversations/sieve-filter
index cf5ff04..c64b574 100755
--- a/conversations/sieve-filter
+++ b/conversations/sieve-filter
@@ -1,8 +1,8 @@
 #!/usr/bin/env python
 
 import sys
-import requests
 
+import requests
 
 if len(sys.argv) != 2:
     print("Usage: %s KEY@URL" % sys.argv[0])
@@ -11,7 +11,7 @@ if len(sys.argv) != 2:
 key, url = sys.argv[1].split('@')
 
 email = sys.stdin.buffer.raw.read()
-sys.stdout.buffer.write(email) # DO NOT REMOVE
+sys.stdout.buffer.write(email)  # DO NOT REMOVE
 
 requests.post(
     url,
diff --git a/conversations/signals.py b/conversations/signals.py
index 5a47df8..27fc328 100644
--- a/conversations/signals.py
+++ b/conversations/signals.py
@@ -1,11 +1,11 @@
 from django.contrib.auth.models import User
+from django.db.models import Q
 from django.db.models.signals import post_save
 from django.dispatch import receiver
-from django.db.models import Q
 
 from accounts.models import Participation
 from proposals.models import Talk
-from proposals.signals import *
+from proposals.signals import talk_added, talk_edited
 
 from .models import ConversationAboutTalk, ConversationWithParticipant, Message
 
diff --git a/conversations/views.py b/conversations/views.py
index 32b7479..2ab2d49 100644
--- a/conversations/views.py
+++ b/conversations/views.py
@@ -6,8 +6,8 @@ from django.core.exceptions import PermissionDenied
 from django.core.urlresolvers import reverse
 from django.shortcuts import get_object_or_404, redirect, render
 
+from accounts.decorators import staff_required
 from accounts.models import Participation
-from accounts.decorators import orga_required, staff_required
 from proposals.models import Talk
 
 from .forms import MessageForm
@@ -66,7 +66,8 @@ def talk_conversation(request, talk):
 @login_required
 def correspondents(request):
 
-    correspondent_list = Participation.objects.filter(site=get_current_site(request), conversation__subscribers=request.user)
+    correspondent_list = Participation.objects.filter(site=get_current_site(request),
+                                                      conversation__subscribers=request.user)
 
     return render(request, 'conversations/correspondents.html', {
             'correspondent_list': correspondent_list,
diff --git a/proposals/forms.py b/proposals/forms.py
index c4a0a0c..6f64970 100644
--- a/proposals/forms.py
+++ b/proposals/forms.py
@@ -5,9 +5,6 @@ from django_select2.forms import Select2TagWidget
 
 from proposals.models import Talk, Topic
 
-__all__ = ['TalkForm', 'TopicCreateForm', 'TopicUpdateForm']
-
-
 TalkForm = modelform_factory(Talk, fields=['title', 'description', 'topics', 'event', 'speakers'],
                              widgets={'topics': CheckboxSelectMultiple(), 'speakers': Select2TagWidget()})
 
diff --git a/proposals/models.py b/proposals/models.py
index 4bbedff..8c2cb9e 100644
--- a/proposals/models.py
+++ b/proposals/models.py
@@ -13,8 +13,6 @@ from ponyconf.utils import PonyConfModel, enum_to_choices
 
 from .utils import query_sum
 
-__all__ = ['Topic', 'Talk']
-
 
 class Topic(PonyConfModel):
 
@@ -72,7 +70,7 @@ class Talk(PonyConfModel):
 class Vote(PonyConfModel):
 
     talk = models.ForeignKey(Talk)
-    user = models.ForeignKey(Participation)
+    user = models.ForeignKey(User)
     vote = models.IntegerField(validators=[MinValueValidator(-2), MaxValueValidator(2)], default=0)
 
     class Meta:
diff --git a/proposals/signals.py b/proposals/signals.py
index 7645c28..05dd411 100644
--- a/proposals/signals.py
+++ b/proposals/signals.py
@@ -1,13 +1,9 @@
-from django.dispatch import Signal, receiver
 from django.db.models.signals import m2m_changed
+from django.dispatch import Signal, receiver
 
-
-from .models import Talk, Topic
 from accounts.models import Participation
 
-
-__all__ = [ 'talk_added', 'talk_edited' ]
-
+from .models import Talk, Topic
 
 talk_added = Signal(providing_args=["sender", "instance", "author"])
 talk_edited = Signal(providing_args=["sender", "instance", "author"])
diff --git a/proposals/tests.py b/proposals/tests.py
index 8664140..82c1c4a 100644
--- a/proposals/tests.py
+++ b/proposals/tests.py
@@ -1,7 +1,7 @@
 from django.contrib.auth.models import User
+from django.contrib.sites.models import Site
 from django.core.urlresolvers import reverse
 from django.test import TestCase
-from django.contrib.sites.models import Site
 
 from accounts.models import Participation
 
@@ -56,17 +56,17 @@ class ProposalsTests(TestCase):
 
         # Talk.is_{editable,moderable}_by
         a, b, c = User.objects.all()
-        self.assertTrue(talk.is_editable_by(c)) # c is superuser
-        self.assertTrue(talk.is_moderable_by(c)) # c is superuser
-        self.assertFalse(talk.is_editable_by(b)) # b is not speaker
-        self.assertFalse(talk.is_moderable_by(b)) # b is not orga
+        self.assertTrue(talk.is_editable_by(c))  # c is superuser
+        self.assertTrue(talk.is_moderable_by(c))  # c is superuser
+        self.assertFalse(talk.is_editable_by(b))  # b is not speaker
+        self.assertFalse(talk.is_moderable_by(b))  # b is not orga
         self.client.login(username='a', password='a')
         self.client.post(reverse('edit-talk', kwargs={'talk': 'super-talk'}),
                          {'title': 'mega talk', 'description': 'mega', 'event': 1, 'speakers': (a.pk, b.pk)})
         talk = Talk.objects.get(slug='super-talk')
         self.assertTrue(b in talk.speakers.all())
-        self.assertTrue(talk.is_editable_by(b)) # b is speaker now
-        self.assertFalse(talk.is_moderable_by(b)) # b is not orga
+        self.assertTrue(talk.is_editable_by(b))  # b is speaker now
+        self.assertFalse(talk.is_moderable_by(b))  # b is not orga
 
     def test_topic_edition_permissions(self):
         # Only orga and superuser can edit topics
@@ -75,6 +75,6 @@ class ProposalsTests(TestCase):
         self.assertEqual(self.client.get(reverse('edit-topic', kwargs={'slug': 'topipo'})).status_code, 302)
         Participation.objects.filter(user__username='b').update(orga=True)
         self.assertEqual(self.client.get(reverse('edit-topic', kwargs={'slug': 'topipo'})).status_code, 200)
-        self.client.login(username='c', password='c') # superuser
+        self.client.login(username='c', password='c')  # superuser
         self.assertEqual(self.client.get(reverse('edit-topic', kwargs={'slug': 'topipo'})).status_code, 200)
         self.assertEqual(self.client.get(reverse('list-topics')).status_code, 200)
diff --git a/proposals/utils.py b/proposals/utils.py
index 2f41c8f..adc7969 100644
--- a/proposals/utils.py
+++ b/proposals/utils.py
@@ -1,6 +1,6 @@
+from django.contrib.sites.shortcuts import get_current_site
 from django.db.models import Q, Sum
 from django.db.models.functions import Coalesce
-from django.contrib.sites.shortcuts import get_current_site
 
 from accounts.models import Participation
 
@@ -10,7 +10,6 @@ def query_sum(queryset, field):
 
 
 def allowed_talks(talks, request):
-    participation = Participation.objects.get(site=get_current_site(request), user=request.user)
-    if not participation.is_orga():
-        talks = talks.filter(Q(topics__reviewers=participation.user) | Q(speakers=request.user) | Q(proposer=request.user))
+    if not Participation.objects.get(site=get_current_site(request), user=request.user).is_orga():
+        talks = talks.filter(Q(topics__reviewers=request.user) | Q(speakers=request.user) | Q(proposer=request.user))
     return talks.distinct()
diff --git a/proposals/views.py b/proposals/views.py
index 07a5e78..a456592 100644
--- a/proposals/views.py
+++ b/proposals/views.py
@@ -8,17 +8,13 @@ from django.core.urlresolvers import reverse
 from django.db.models import Q
 from django.shortcuts import get_object_or_404, redirect, render
 from django.views.generic import CreateView, DetailView, ListView, UpdateView
-from django.http import JsonResponse
-from django.core.exceptions import ObjectDoesNotExist
 
-from accounts.mixins import OrgaRequiredMixin, StaffRequiredMixin, SuperuserRequiredMixin
-from accounts.models import Participation
-from accounts.utils import is_orga
+from accounts.mixins import OrgaRequiredMixin, StaffRequiredMixin
 
 from .forms import TalkForm, TopicCreateForm, TopicUpdateForm
 from .models import Talk, Topic, Vote
+from .signals import talk_added, talk_edited
 from .utils import allowed_talks
-from .signals import *
 
 
 def home(request):
@@ -27,9 +23,10 @@ def home(request):
 
 @login_required
 def talk_list(request):
+    talks = Talk.objects.filter(site=get_current_site(request))
     return render(request, 'proposals/talks.html', {
-        'my_talks': Talk.objects.filter(site=get_current_site(request)).filter(Q(speakers=request.user) | Q(proposer=request.user)).distinct(),
-        'other_talks': allowed_talks(Talk.objects.filter(site=get_current_site(request)).exclude(speakers=request.user, proposer=request.user), request)
+        'my_talks': talks.filter(Q(speakers=request.user) | Q(proposer=request.user)).distinct(),
+        'other_talks': allowed_talks(talks.exclude(Q(speakers=request.user) | Q(proposer=request.user)), request)
     })
 
 
@@ -74,19 +71,16 @@ class TalkDetail(LoginRequiredMixin, DetailView):
         return Talk.objects.filter(site=get_current_site(self.request)).all()
 
     def get_context_data(self, **ctx):
-        user = self.request.user
-        if self.object.is_moderable_by(user):
-            vote = Vote.objects.filter(talk=self.object, user=Participation.objects.get(site=get_current_site(self.request), user=user)).first()
+        if self.object.is_moderable_by(self.request.user):
+            vote = Vote.objects.filter(talk=self.object, user=self.request.user).first()
             ctx.update(edit_perm=True, moderate_perm=True, vote=vote,
                        form_url=reverse('talk-conversation', kwargs={'talk': self.object.slug}))
         else:
-            ctx['edit_perm'] = self.object.is_editable_by(user)
+            ctx['edit_perm'] = self.object.is_editable_by(self.request.user)
         return super().get_context_data(**ctx)
 
 
 class TopicMixin(object):
-    model = Topic
-
     def get_queryset(self):
         return Topic.objects.filter(site=get_current_site(self.request)).all()
 
@@ -96,10 +90,12 @@ class TopicList(LoginRequiredMixin, TopicMixin, ListView):
 
 
 class TopicCreate(OrgaRequiredMixin, TopicMixin, CreateView):
+    model = Topic
     form_class = TopicCreateForm
+
     def form_valid(self, form):
         form.instance.site = get_current_site(self.request)
-        return super(TopicCreate, self).form_valid(form)
+        return super().form_valid(form)
 
 
 class TopicUpdate(OrgaRequiredMixin, TopicMixin, UpdateView):
@@ -111,18 +107,16 @@ class SpeakerList(StaffRequiredMixin, ListView):
     template_name = 'proposals/speaker_list.html'
 
     def get_queryset(self):
-        current_site = get_current_site(self.request)
-        return User.objects.filter(talk__in=Talk.objects.filter(site=current_site)).all().distinct()
+        site = get_current_site(self.request)
+        return User.objects.filter(talk__in=Talk.objects.filter(site=site)).all().distinct()
 
 
 @login_required
 def vote(request, talk, score):
-    current_site = get_current_site(request)
-    talk = get_object_or_404(Talk, site=current_site, slug=talk)
-    user = Participation.objects.get(site=current_site, user=request.user)
+    talk = get_object_or_404(Talk, site=get_current_site(request), slug=talk)
     if not talk.is_moderable_by(request.user):
         raise PermissionDenied()
-    vote, created = Vote.objects.get_or_create(talk=talk, user=user)
+    vote, created = Vote.objects.get_or_create(talk=talk, user=request.user)
     vote.vote = int(score)
     vote.save()
     messages.success(request, "Vote successfully %s" % ('created' if created else 'updated'))