diff --git a/app/api/assiduites.py b/app/api/assiduites.py
index 17ccf816c..044931b68 100644
--- a/app/api/assiduites.py
+++ b/app/api/assiduites.py
@@ -249,11 +249,10 @@ def assiduites_group(with_query: bool = False):
     if with_query:
         assiduites_query = _filter_manager(request, assiduites_query)
 
-    data_set: dict[list[dict]] = {key: [] for key in etuds}
+    data_set: dict[list[dict]] = {str(key): [] for key in etuds}
     for ass in assiduites_query.all():
         data = ass.to_dict(format_api=True)
-        data_set.get(data["etudid"]).append(data)
-
+        data_set.get(str(data["etudid"])).append(data)
     return data_set