diff --git a/cotisations/forms.py b/cotisations/forms.py
index 4c4721a8..d7a2e2ba 100644
--- a/cotisations/forms.py
+++ b/cotisations/forms.py
@@ -42,6 +42,7 @@ from django.forms import ModelForm, Form
 from django.core.validators import MinValueValidator
 from django.utils.translation import ugettext as _
 from django.utils.translation import ugettext_lazy as _l
+from django.shortcuts import get_object_or_404
 
 from re2o.field_permissions import FieldPermissionFormMixin
 from re2o.mixins import FormRevMixin
diff --git a/cotisations/payment_methods/forms.py b/cotisations/payment_methods/forms.py
index 0a3f1dd2..d4d55a74 100644
--- a/cotisations/payment_methods/forms.py
+++ b/cotisations/payment_methods/forms.py
@@ -30,7 +30,7 @@ def payment_method_factory(payment, *args, creation=True, **kwargs):
 
     If the payment has a payment method, returns a ModelForm of it. Else if
     it is the creation of the payment, a `PaymentMethodForm`.
-    Else an empty form.
+    Else `None`.
 
     Args:
         payment: The payment
@@ -39,7 +39,7 @@ def payment_method_factory(payment, *args, creation=True, **kwargs):
         **kwargs: passed to the form
 
     Returns:
-        A form
+        A form or None
     """
     payment_method = kwargs.pop('instance', find_payment_method(payment))
     if payment_method is not None:
@@ -50,8 +50,6 @@ def payment_method_factory(payment, *args, creation=True, **kwargs):
         )
     elif creation:
         return PaymentMethodForm(*args, **kwargs)
-    else:
-        return forms.Form()
 
 
 class PaymentMethodForm(forms.Form):
diff --git a/cotisations/views.py b/cotisations/views.py
index c6403a1f..8b9fe79e 100644
--- a/cotisations/views.py
+++ b/cotisations/views.py
@@ -463,9 +463,11 @@ def edit_paiement(request, paiement_instance, **_kwargs):
         creation=False
     )
 
-    if payment.is_valid() and payment_method.is_valid():
+    if payment.is_valid() and \
+       (payment_method is None or payment_method.is_valid()):
         payment.save()
-        payment_method.save()
+        if payment_method is not None:
+            payment_method.save()
         messages.success(
             request,
             _("The payement method has been successfully edited.")