diff --git a/src/agenda_culturel/forms.py b/src/agenda_culturel/forms.py
index acc858d..d6d58ea 100644
--- a/src/agenda_culturel/forms.py
+++ b/src/agenda_culturel/forms.py
@@ -609,7 +609,7 @@ class MergeDuplicates(Form):
         result += '<input id="' + id + '" name="' + key + '"'
         if key in MergeDuplicates.checkboxes_fields:
             result += ' type="checkbox"'
-            if value in checked:
+            if checked and value in checked:
                 result += " checked"
         else:
             result += ' type="radio"'