diff --git a/app/templates/assiduites/widgets/timeline.j2 b/app/templates/assiduites/widgets/timeline.j2
index 3a4507085..9d614195f 100644
--- a/app/templates/assiduites/widgets/timeline.j2
+++ b/app/templates/assiduites/widgets/timeline.j2
@@ -131,12 +131,12 @@
             document.addEventListener(
                 "mouseup",
                 mouseUp,
-                {once:true}
+                { once: true }
             );
             document.addEventListener(
                 "touchend",
                 mouseUp,
-                {once:true}
+                { once: true }
 
             );
         } else if (event.target === periodTimeLine) {
@@ -217,6 +217,14 @@
     }
 
     function setPeriodValues(deb, fin) {
+        if (fin < deb) {
+            throw new RangeError(`le paramètre 'deb' doit être inférieur au paramètre 'fin' ([${deb};${fin}])`)
+        }
+
+        if (deb < 0 || fin < 0) {
+            throw new RangeError(`Les paramètres doivent être des entiers positifis ([${deb};${fin}])`)
+        }
+
         deb = snapToQuarter(deb);
         fin = snapToQuarter(fin);
         let leftPercentage = (deb - t_start) / (t_end - t_start) * 100;
@@ -231,13 +239,13 @@
 
     function snapHandlesToQuarters() {
         const periodValues = getPeriodValues();
-        let lef = Math.min(computePercentage(periodValues[0], t_start), computePercentage(t_end, tick_delay));
+        let lef = Math.min(computePercentage(Math.abs(periodValues[0]), t_start), computePercentage(Math.abs(t_end), tick_delay));
         if (lef < 0) {
             lef = 0;
         }
         const left = `${lef}%`;
 
-        let wid = Math.max(computePercentage(periodValues[1], periodValues[0]), computePercentage(tick_delay, 0));
+        let wid = Math.max(computePercentage(Math.abs(periodValues[1]), Math.abs(periodValues[0])), computePercentage(tick_delay, 0));
         if (wid > 100) {
             wid = 100;
         }
@@ -251,10 +259,23 @@
     function computePercentage(a, b) {
         return ((a - b) / (t_end - t_start)) * 100;
     }
+    function fromTime(time, separator = ":") {
+        const [hours, minutes] = time.split(separator).map((el) => Number(el))
+        return hours + minutes / 60
+    }
 
     createTicks();
     setPeriodValues(t_start, t_start + period_default);
 
+    {% if heures %}
+    let [heure_deb, heure_fin] = [{{ heures | safe }}]
+    if (heure_deb != '' && heure_fin != '') {
+        heure_deb = fromTime(heure_deb);
+        heure_fin = fromTime(heure_fin);
+        setPeriodValues(heure_deb, heure_fin)
+    }
+    {% endif %}
+
 </script>
 <style>
     .timeline-container {
diff --git a/app/views/assiduites.py b/app/views/assiduites.py
index da56a2e69..88a482adc 100644
--- a/app/views/assiduites.py
+++ b/app/views/assiduites.py
@@ -262,6 +262,10 @@ def signal_assiduites_etud():
 
     # Récupération de la date (par défaut la date du jour)
     date = request.args.get("date", datetime.date.today().isoformat())
+    heures: list[str] = [
+        request.args.get("heure_deb", ""),
+        request.args.get("heure_fin", ""),
+    ]
 
     # gestion évaluations (Appel à la page depuis les évaluations)
 
@@ -320,7 +324,7 @@ def signal_assiduites_etud():
             date=date,
             morning=morning,
             lunch=lunch,
-            timeline=_timeline(),
+            timeline=_timeline(heures=",".join([f"'{s}'" for s in heures])),
             afternoon=afternoon,
             nonworkdays=_non_work_days(),
             forcer_module=sco_preferences.get_preference(
@@ -576,6 +580,10 @@ def signal_assiduites_group():
     formsemestre_id: int = request.args.get("formsemestre_id", -1)
     moduleimpl_id: int = request.args.get("moduleimpl_id")
     date: str = request.args.get("jour", datetime.date.today().isoformat())
+    heures: list[str] = [
+        request.args.get("heure_deb", ""),
+        request.args.get("heure_fin", ""),
+    ]
     group_ids: list[int] = request.args.get("group_ids", None)
     if group_ids is None:
         group_ids = []
@@ -701,7 +709,7 @@ def signal_assiduites_group():
             formsemestre_id=formsemestre_id,
             grp=sco_groups_view.menu_groups_choice(groups_infos),
             moduleimpl_select=_module_selector(formsemestre, moduleimpl_id),
-            timeline=_timeline(),
+            timeline=_timeline(heures=",".join([f"'{s}'" for s in heures])),
             nonworkdays=_non_work_days(),
             formsemestre_date_debut=str(formsemestre.date_debut),
             formsemestre_date_fin=str(formsemestre.date_fin),
@@ -1259,12 +1267,12 @@ def generate_bul_list(etud: Identite, semestre: FormSemestre) -> str:
         assiduites, metric=metrique, filtered={"split": True}
     )
 
-    # On sépare : 
+    # On sépare :
     # - abs_j = absences justifiées
     # - abs_nj = absences non justifiées
     # - retards = les retards
     # - justifs = les justificatifs
-    
+
     abs_j: list[str] = [
         {"date": _get_date_str(assi.date_debut, assi.date_fin)}
         for assi in assiduites
@@ -1463,7 +1471,7 @@ def _dynamic_module_selector() -> str:
     )
 
 
-def _timeline(formsemestre_id: int = None) -> str:
+def _timeline(formsemestre_id: int = None, heures=None) -> str:
     """
     _timeline retourne l'html de la timeline
 
@@ -1483,6 +1491,7 @@ def _timeline(formsemestre_id: int = None) -> str:
         periode_defaut=sco_preferences.get_preference(
             "periode_defaut", formsemestre_id
         ),
+        heures=heures,
     )