diff --git a/app/views/scodoc.py b/app/views/scodoc.py
index 339e5cd3e6..7e2c9d1631 100644
--- a/app/views/scodoc.py
+++ b/app/views/scodoc.py
@@ -203,8 +203,15 @@ def config_assiduites():
             flash("Heure de midi enregistrée")
         if ScoDocSiteConfig.set("assi_afternoon_time", form.data["afternoon_time"]):
             flash("Heure de fin de la journée enregistrée")
-        if ScoDocSiteConfig.set("assi_tick_time", form.data["tick_time"]):
+        if (
+            form.data["tick_time"] > 0
+            and form.data["tick_time"] < 60
+            and ScoDocSiteConfig.set("assi_tick_time", float(form.data["tick_time"]))
+        ):
             flash("Granularité de la timeline enregistrée")
+        else:
+            flash("Erreur : Granularité invalide ou identique")
+
         return redirect(url_for("scodoc.configuration"))
 
     elif request.method == "GET":
@@ -217,7 +224,12 @@ def config_assiduites():
         form.afternoon_time.data = ScoDocSiteConfig.get(
             "assi_afternoon_time", datetime.time(18, 0, 0)
         )
-        form.tick_time.data = float(ScoDocSiteConfig.get("assi_tick_time", 15))
+        try:
+            form.tick_time.data = float(ScoDocSiteConfig.get("assi_tick_time", 15.0))
+        except ValueError:
+            form.tick_time.data = 15.0
+            ScoDocSiteConfig.set("assi_tick_time", 15.0)
+
         return render_template(
             "assiduites/config_assiduites.j2",
             form=form,