diff --git a/kfet/views.py b/kfet/views.py
index cd867bf5..b7623708 100644
--- a/kfet/views.py
+++ b/kfet/views.py
@@ -44,7 +44,7 @@ def account(request):
 @login_required
 @permission_required('kfet.is_team')
 def account_is_validandfree_ajax(request):
-    if not request.GET.get("trigramme"):
+    if not request.GET.get("trigramme", ''):
         raise Http404
     trigramme = request.GET.get("trigramme")
     data = Account.is_validandfree(trigramme)
@@ -118,7 +118,7 @@ def account_create_ajax(request, username=None, login_clipper=None):
     user = None
     if login_clipper:
         # à partir d'un clipper
-        # le user associé à ce clipper ne devrait pas encore existé
+        # le user associé à ce clipper ne devrait pas encore exister
         clipper = get_object_or_404(Clipper, username = login_clipper)
         try:
             # Vérification que clipper ne soit pas déjà dans User
@@ -132,7 +132,7 @@ def account_create_ajax(request, username=None, login_clipper=None):
             # UserForm - Prefill + Création
             user_initial_data = {
                     'username' : login_clipper,
-                    'email'    : login_clipper + "@clipper.ens.fr"}
+                    'email'    : "%s@clipper.ens.fr" % login_clipper}
             if clipper.fullname:
                 # Prefill du nom et prénom
                 names = clipper.fullname.split()
@@ -180,10 +180,7 @@ def account_create_ajax(request, username=None, login_clipper=None):
 
 @login_required
 def account_read(request, trigramme):
-    try:
-        account = Account.objects.get(trigramme=trigramme)
-    except Account.DoesNotExist:
-        raise Http404
+    account = get_object_or_404(Account, trigramme=trigramme)
 
     # Checking permissions
     if not request.user.has_perm('kfet.is_team') \
@@ -196,10 +193,7 @@ def account_read(request, trigramme):
 
 @login_required
 def account_update(request, trigramme):
-    try:
-        account = Account.objects.get(trigramme=trigramme)
-    except Account.DoesNotExist:
-        raise Http404
+    account = get_object_or_404(Account, trigramme=trigramme)
 
     # Checking permissions
     if not request.user.has_perm('kfet.is_team') \
@@ -278,7 +272,7 @@ class CheckoutCreate(SuccessMessageMixin, CreateView):
     # Surcharge de la validation
     def form_valid(self, form):
         # Checking permission
-        if not self.request.user.has_perm('add_checkout'):
+        if not self.request.user.has_perm('kfet.add_checkout'):
             raise PermissionDenied
         # Creating
         form.instance.created_by = self.request.user.profile.account_kfet
@@ -302,7 +296,7 @@ class CheckoutUpdate(SuccessMessageMixin, UpdateView):
     # Surcharge de la validation
     def form_valid(self, form):
         # Checking permission
-        if not self.request.user.has_perm('change_checkout'):
+        if not self.request.user.has_perm('kfet.change_checkout'):
             raise PermissionDenied
         # Updating
         return super(CheckoutUpdate, self).form_valid(form)