diff --git a/src/agenda_culturel/views.py b/src/agenda_culturel/views.py
index aba6d32..9dc456f 100644
--- a/src/agenda_culturel/views.py
+++ b/src/agenda_culturel/views.py
@@ -1730,18 +1730,22 @@ def apply_categorisation_rules(request):
     else:
         # first we check if events are not correctly categorised
         to_categorise = []
-        for e in Event.objects.filter(start_day__gte=datetime.now()).exclude(category=Category.get_default_category_id()):
+        for e in Event.objects.filter(start_day__gte=datetime.now()).exclude(category=Category.get_default_category_id()).exclude(category=None):
             c = CategorisationRule.get_category_from_rules(e)
             if c and c != e.category:
                 to_categorise.append((e, c))
 
         # then we apply rules on events without category
         nb = 0
-        for e in Event.objects.filter(start_day__gte=datetime.now()).filter(category=Category.get_default_category_id()):
+        to_save = []
+        for e in Event.objects.filter(start_day__gte=datetime.now()).filter(Q(category=Category.get_default_category_id()) | Q(category=None)):
             success = CategorisationRule.apply_rules(e)
             if success:
                 nb += 1
-                e.save()
+                to_save.append(e)
+        
+        if nb != 0:
+            Event.objects.bulk_update(to_save, fields=["category"])
 
         # set messages
         if nb != 0: