diff --git a/app/scodoc/sco_compute_moy.py b/app/scodoc/sco_compute_moy.py
index ae821068fc..94d1f1f36d 100644
--- a/app/scodoc/sco_compute_moy.py
+++ b/app/scodoc/sco_compute_moy.py
@@ -348,7 +348,7 @@ def do_moduleimpl_moyennes(nt, mod):
             if etudid in eval_rattr["notes"]:
                 note = eval_rattr["notes"][etudid]["value"]
                 if note != None and note != NOTES_NEUTRALISE and note != NOTES_ATTENTE:
-                    if isinstance(R[etudid], float):
+                    if not isinstance(R[etudid], float):
                         R[etudid] = note
                     else:
                         note_sur_20 = note * 20.0 / eval_rattr["note_max"]