diff --git a/app/scodoc/notesdb.py b/app/scodoc/notesdb.py
index e0f246064..5aa5c91ba 100644
--- a/app/scodoc/notesdb.py
+++ b/app/scodoc/notesdb.py
@@ -460,7 +460,8 @@ def dictfilter(d, fields, filter_nulls=True):
 # --- Misc Tools
 
 
-def DateDMYtoISO(dmy: str, null_is_empty=False) -> str | None:  # XXX deprecated
+# XXX deprecated, voir convert_fr_date
+def DateDMYtoISO(dmy: str, null_is_empty=False) -> str | None:
     """Convert date string from french format (or ISO) to ISO.
     If null_is_empty (default false), returns "" if no input.
     """
@@ -479,7 +480,7 @@ def DateDMYtoISO(dmy: str, null_is_empty=False) -> str | None:  # XXX deprecated
         try:
             dt = datetime.datetime.fromisoformat(dmy)
         except ValueError as exc:
-            raise ScoValueError(f'Date (j/m/a or iso) invalide: "{dmy}"') from exc
+            raise ValueError(f'Date (j/m/a or iso) invalide: "{dmy}"') from exc
     return dt.date().isoformat()
 
 
diff --git a/app/scodoc/sco_evaluation_edit.py b/app/scodoc/sco_evaluation_edit.py
index 3824ca60f..2b47e1312 100644
--- a/app/scodoc/sco_evaluation_edit.py
+++ b/app/scodoc/sco_evaluation_edit.py
@@ -374,13 +374,7 @@ def evaluation_create_form(
         args = tf[2]
         # modifie le codage des dates
         # (nb: ce formulaire ne permet de créer que des évaluation sur la même journée)
-        if args.get("jour"):
-            try:
-                date_debut = datetime.datetime.strptime(args["jour"], "%d/%m/%Y")
-            except ValueError as exc:
-                raise ScoValueError("Date (j/m/a) invalide") from exc
-        else:
-            date_debut = None
+        date_debut = scu.convert_fr_date(args["jour"]) if args.get("jour") else None
         args["date_debut"] = date_debut
         args["date_fin"] = date_debut  # même jour
         args.pop("jour", None)
diff --git a/app/scodoc/sco_formsemestre_edit.py b/app/scodoc/sco_formsemestre_edit.py
index c8de7b9f5..6ee355137 100644
--- a/app/scodoc/sco_formsemestre_edit.py
+++ b/app/scodoc/sco_formsemestre_edit.py
@@ -812,14 +812,18 @@ def do_formsemestre_createwithmodules(edit=False, formsemestre: FormSemestre = N
     )
     msg = ""
     if tf[0] == 1:
-        # check dates
-        if ndb.DateDMYtoISO(tf[2]["date_debut"]) > ndb.DateDMYtoISO(tf[2]["date_fin"]):
-            msg = '<ul class="tf-msg"><li class="tf-msg">Dates de début et fin incompatibles !</li></ul>'
+        # convert and check dates
+        tf[2]["date_debut"] = scu.convert_fr_date(tf[2]["date_debut"])
+        tf[2]["date_fin"] = scu.convert_fr_date(tf[2]["date_fin"])
+        if tf[2]["date_debut"] > tf[2]["date_fin"]:
+            msg = """<ul class="tf-msg">
+                    <li class="tf-msg">Dates de début et fin incompatibles !</li>
+                </ul>"""
 
         if (
             sco_preferences.get_preference("always_require_apo_sem_codes")
             and not any(
-                [tf[2]["etape_apo" + str(n)] for n in range(0, scu.EDIT_NB_ETAPES + 1)]
+                tf[2]["etape_apo" + str(n)] for n in range(0, scu.EDIT_NB_ETAPES + 1)
             )
             # n'impose pas d'Apo pour les sem. extérieurs
             and ((formsemestre is None) or formsemestre.modalite != "EXT")
diff --git a/app/scodoc/sco_utils.py b/app/scodoc/sco_utils.py
index 51d8a5d43..fa2ae54a7 100644
--- a/app/scodoc/sco_utils.py
+++ b/app/scodoc/sco_utils.py
@@ -109,6 +109,38 @@ ETATS_INSCRIPTION = {
 }
 
 
+def convert_fr_date(date_str: str, allow_iso=True) -> datetime.datetime:
+    """Converti une date saisie par un humain français avant 2070
+    en un objet datetime.
+    12/2/1972 => 1972-02-12, 12/2/72 => 1972-02-12, mais 12/2/24 => 2024-02-12
+    Le pivot est 70.
+    ScoValueError si date invalide.
+    """
+    try:
+        return datetime.datetime.strptime(date_str, "%d/%m/%Y")
+    except ValueError:
+        # Try to add century ?
+        m = re.match(r"^(\d{1,2})/(\d{1,2})/(\d\d)$", date_str)
+        if m:
+            year = int(m.group(3))
+            if year < 70:
+                year += 2000
+            else:
+                year += 1900
+            try:
+                return datetime.datetime.strptime(
+                    f"{m.group(1)}/{m.group(2)}/{year}", "%d/%m/%Y"
+                )
+            except ValueError:
+                pass
+    if allow_iso:
+        try:
+            return datetime.datetime.fromisoformat(date_str)
+        except ValueError as exc:
+            raise ScoValueError("Date (j/m/a or ISO) invalide") from exc
+    raise ScoValueError("Date (j/m/a) invalide")
+
+
 def print_progress_bar(
     iteration,
     total,