diff --git a/app/scodoc/sco_import_etuds.py b/app/scodoc/sco_import_etuds.py
index 1107b11f..0bd9d447 100644
--- a/app/scodoc/sco_import_etuds.py
+++ b/app/scodoc/sco_import_etuds.py
@@ -548,6 +548,12 @@ def _import_one_student(
     else:
         args["formsemestre_id"] = values["codesemestre"]
         formsemestre_id = values["codesemestre"]
+    try:
+        formsemestre_id = int(formsemestre_id)
+    except ValueError as exc:
+        raise ScoValueError(
+            f"valeur invalide dans la colonne codesemestre, ligne {linenum+1}"
+        ) from exc
     # recupere liste des groupes:
     if formsemestre_id not in GroupIdInferers:
         GroupIdInferers[formsemestre_id] = sco_groups.GroupIdInferer(formsemestre_id)