diff --git a/app/scodoc/sco_formsemestre_edit.py b/app/scodoc/sco_formsemestre_edit.py
index a9f46380..a0f534dd 100644
--- a/app/scodoc/sco_formsemestre_edit.py
+++ b/app/scodoc/sco_formsemestre_edit.py
@@ -1678,7 +1678,7 @@ def formsemestre_edit_uecoefs(formsemestre_id, err_ue_id=None):
     sum_coefs_by_ue_id = {}
     for ue in ues:
         sum_coefs_by_ue_id[ue.id] = sum(
-            modimpl.module.coefficient
+            modimpl.module.coefficient or 0.0
             for modimpl in modimpls
             if modimpl.module.ue_id == ue.id
         )