diff --git a/src/agenda_culturel/calendar.py b/src/agenda_culturel/calendar.py
index 137462a..c3dfe80 100644
--- a/src/agenda_culturel/calendar.py
+++ b/src/agenda_culturel/calendar.py
@@ -242,7 +242,7 @@ class CalendarList:
             Q(other_versions__isnull=True) |
             Q(other_versions__representative=F('pk')) |
             Q(other_versions__representative__isnull=True)
-        ).order_by("start_time", "title__unaccent__lower").prefetch_related("exact_location").prefetch_related("category").prefetch_related("other_versions").prefetch_related("other_versions__representative")
+        ).order_by("start_time", "title__unaccent__lower").select_related("exact_location").select_related("category").select_related("other_versions").select_related("other_versions__representative")
 
         firstdate = datetime.fromordinal(self.c_firstdate.toordinal())
         if firstdate.tzinfo is None or firstdate.tzinfo.utcoffset(firstdate) is None:
diff --git a/src/agenda_culturel/models.py b/src/agenda_culturel/models.py
index d529e99..fb343c4 100644
--- a/src/agenda_culturel/models.py
+++ b/src/agenda_culturel/models.py
@@ -1978,7 +1978,7 @@ class CategorisationRule(models.Model):
     def get_category_from_rules(event):
         cats = defaultdict(lambda: 0)
         if CategorisationRule.rules is None:
-            CategorisationRule.rules = CategorisationRule.objects.all().prefetch_related("category").prefetch_related("place")
+            CategorisationRule.rules = CategorisationRule.objects.all().select_related("category").select_related("place")
 
         for rule in CategorisationRule.rules:
             if rule.match(event):
diff --git a/src/agenda_culturel/views.py b/src/agenda_culturel/views.py
index 66076d2..580968a 100644
--- a/src/agenda_culturel/views.py
+++ b/src/agenda_culturel/views.py
@@ -1492,7 +1492,7 @@ def set_duplicate(request, year, month, day, pk):
 @login_required(login_url="/accounts/login/")
 @permission_required("agenda_culturel.view_categorisationrule")
 def categorisation_rules(request):
-    paginator = Paginator(CategorisationRule.objects.all().order_by("pk").prefetch_related("category").prefetch_related("place"), 100)
+    paginator = Paginator(CategorisationRule.objects.all().order_by("pk").select_related("category").select_related("place"), 100)
     page = request.GET.get("page")
 
     try:
@@ -1584,7 +1584,7 @@ def apply_categorisation_rules(request):
     else:
         # first we check if events are not correctly categorised
         to_categorise = []
-        events = Event.objects.filter(start_day__gte=datetime.now()).exclude(category=Category.get_default_category_id()).exclude(category=None).prefetch_related("exact_location").prefetch_related("category")
+        events = Event.objects.filter(start_day__gte=datetime.now()).exclude(category=Category.get_default_category_id()).exclude(category=None).select_related("exact_location").select_related("category")
         for e in events:
             c = CategorisationRule.get_category_from_rules(e)
             if c and c != e.category:
@@ -1593,7 +1593,7 @@ def apply_categorisation_rules(request):
         # then we apply rules on events without category
         nb = 0
         to_save = []
-        events = Event.objects.filter(start_day__gte=datetime.now()).filter(Q(category=Category.get_default_category_id()) | Q(category=None)).prefetch_related("exact_location").prefetch_related("category")
+        events = Event.objects.filter(start_day__gte=datetime.now()).filter(Q(category=Category.get_default_category_id()) | Q(category=None)).select_related("exact_location").select_related("category")
         for e in events:
             success = CategorisationRule.apply_rules(e)
             if success: