diff --git a/src/agenda_culturel/calendar.py b/src/agenda_culturel/calendar.py
index aa110f6..ca39f5c 100644
--- a/src/agenda_culturel/calendar.py
+++ b/src/agenda_culturel/calendar.py
@@ -4,6 +4,7 @@ from django.db.models import Q, F
 from django.utils import timezone
 from django.utils.translation import gettext_lazy as _
 from django.template.defaultfilters import date as _date
+from django.http import Http404
 
 from django.db.models import CharField
 from django.db.models.functions import Lower
@@ -347,8 +348,11 @@ class CalendarWeek(CalendarList):
         self.year = year
         self.week = week
 
-        first = date.fromisocalendar(self.year, self.week, 1)
-        last = date.fromisocalendar(self.year, self.week, 7)
+        try:
+            first = date.fromisocalendar(self.year, self.week, 1)
+            last = date.fromisocalendar(self.year, self.week, 7)
+        except:
+            raise Http404()
 
         super().__init__(first, last, filter, qs)