diff --git a/app/auth/models.py b/app/auth/models.py
index bd387548..8ee5bef7 100644
--- a/app/auth/models.py
+++ b/app/auth/models.py
@@ -159,7 +159,7 @@ class User(UserMixin, db.Model):
         """
         for field in ["nom", "prenom", "dept", "active", "email", "date_expiration"]:
             if field in data:
-                setattr(self, field, data[field])
+                setattr(self, field, data[field] or None)
         if new_user:
             if "user_name" in data:
                 # never change name of existing users
diff --git a/app/scodoc/TrivialFormulator.py b/app/scodoc/TrivialFormulator.py
index e8871b12..d780643d 100644
--- a/app/scodoc/TrivialFormulator.py
+++ b/app/scodoc/TrivialFormulator.py
@@ -562,18 +562,11 @@ class TF(object):
                     '<input type="text" name="%s" id="%s" size="%d" %s'
                     % (field, field, size, attribs)
                 )
-                lem.append(('value="%(' + field + ')s" />') % values)
+                lem.append('value="%(' + field + ')s" />' % values)
                 suggest_js.append(
-                    """var %s_opts = %s;
-                    var %s_as = new bsn.AutoSuggest('%s', %s_opts);
-                    """
-                    % (
-                        field,
-                        dict2js(descr.get("text_suggest_options", {})),
-                        field,
-                        field,
-                        field,
-                    )
+                    f"""var {field}_opts = {dict2js(descr.get("text_suggest_options", {}))};
+var {field}_as = new bsn.AutoSuggest('{field}', {field}_opts);
+"""
                 )
             else:
                 raise ValueError("unkown input_type for form (%s)!" % input_type)
diff --git a/app/scodoc/sco_formsemestre_edit.py b/app/scodoc/sco_formsemestre_edit.py
index 6d4120c6..cfd7d51c 100644
--- a/app/scodoc/sco_formsemestre_edit.py
+++ b/app/scodoc/sco_formsemestre_edit.py
@@ -200,7 +200,7 @@ def do_formsemestre_createwithmodules(context, REQUEST=None, edit=False):
         NB_SEM = parcours.NB_SEM
     else:
         NB_SEM = 10  # fallback, max 10 semestres
-    semestre_id_list = [-1] + [str(x) for x in range(1, NB_SEM + 1)]
+    semestre_id_list = ["-1"] + [str(x) for x in range(1, NB_SEM + 1)]
     semestre_id_labels = []
     for sid in semestre_id_list:
         if sid == "-1":
@@ -578,7 +578,7 @@ def do_formsemestre_createwithmodules(context, REQUEST=None, edit=False):
                     itemtemplate = """<tr><td class="tf-fieldlabel">%(label)s</td><td class="tf-field">%(elem)s</td></tr>"""
                 modform.append(
                     (
-                        str(mod["module_id"]),
+                        "MI" + str(mod["module_id"]),
                         {
                             "input_type": "text_suggest",
                             "size": 50,
@@ -738,8 +738,9 @@ def do_formsemestre_createwithmodules(context, REQUEST=None, edit=False):
             formsemestre_id = sco_formsemestre.do_formsemestre_create(tf[2])
             # creation des modules
             for module_id in tf[2]["tf-checked"]:
+                assert module_id[:2] == "MI"
                 modargs = {
-                    "module_id": module_id,
+                    "module_id": int(module_id[2:]),
                     "formsemestre_id": formsemestre_id,
                     "responsable_id": tf[2][module_id],
                 }
@@ -755,7 +756,8 @@ def do_formsemestre_createwithmodules(context, REQUEST=None, edit=False):
             # Note: la destruction echouera s'il y a des objets dependants
             #       (eg des evaluations définies)
             # nouveaux modules
-            checkedmods = tf[2]["tf-checked"]
+            # (retire le "MI" du début du nom de champs)
+            checkedmods = [int(x[2:]) for x in tf[2]["tf-checked"]]
             sco_formsemestre.do_formsemestre_edit(context, tf[2])
             ams = sco_moduleimpl.do_moduleimpl_list(
                 context, formsemestre_id=formsemestre_id
diff --git a/app/views/users.py b/app/views/users.py
index a705f809..69eac225 100644
--- a/app/views/users.py
+++ b/app/views/users.py
@@ -150,7 +150,9 @@ def create_user_form(context, REQUEST, user_name=None, edit=0):
         else:
             initvalues["roles"] = []
         if "date_expiration" in initvalues:
-            initvalues["date_expiration"] = u.date_expiration.strftime("%d/%m/%Y")
+            initvalues["date_expiration"] = (
+                u.date_expiration.strftime("%d/%m/%Y") if u.date_expiration else ""
+            )
         initvalues["status"] = "" if u.active else "old"
         orig_roles = {  # set des roles existants avant édition
             UserRole.role_dept_from_string(role_dept)