diff --git a/app/api/formsemestres.py b/app/api/formsemestres.py
index bdcb46164..c086b6278 100644
--- a/app/api/formsemestres.py
+++ b/app/api/formsemestres.py
@@ -7,6 +7,7 @@ import app
 from app import models
 from app.api import bp
 from app.api.auth import token_auth, token_permission_required
+from app.api.errors import error_response
 from app.comp import res_sem
 from app.comp.moy_mod import ModuleImplResults
 from app.comp.res_compat import NotesTableCompat
@@ -91,7 +92,13 @@ def formsemestre_apo(etape_apo: str):
         FormSemestreEtape.formsemestre_id == FormSemestre.id,
     )
 
-    return jsonify([formsemestre.to_dict() for formsemestre in formsemestres])
+    res = [formsemestre.to_dict() for formsemestre in formsemestres]
+    if len(res) == 0:
+        return error_response(
+            404, message="Aucun formsemestre trouvé avec cette étape apogée"
+        )
+    else:
+        return jsonify(res)
 
 
 @bp.route("/formsemestre/<int:formsemestre_id>/bulletins", methods=["GET"])