diff --git a/itou/approvals/models.py b/itou/approvals/models.py
index bfbc572d1a..d75b44f840 100644
--- a/itou/approvals/models.py
+++ b/itou/approvals/models.py
@@ -558,7 +558,7 @@ def clean(self):
                         "start_at": (
                             f"Pour la date de début de suspension, vous pouvez remonter "
                             f"{self.MAX_RETROACTIVITY_DURATION_DAYS} jours avant la date du jour."
-                            f"Date de début minimum: {next_min_start_at.strftime('%d/%m/%Y')}."
+                            f"Date de début minimum : {next_min_start_at.strftime('%d/%m/%Y')}."
                         )
                     }
                 )
@@ -626,25 +626,20 @@ def next_min_start_at(approval):
         """
         Returns the minimum date on which a suspension can begin.
         """
-        # by default the next min start is the date of last hiring start of user
-        min_suspension_start_at = approval.user.last_accepted_job_application.hiring_start_at
         today = datetime.date.today()
-        # We set the next min to the date of last old suspension if suspension exist
+        # Default starting date.
+        start_at = approval.user.last_accepted_job_application.hiring_start_at
+        start_at_threshold = today - datetime.timedelta(days=Suspension.MAX_RETROACTIVITY_DURATION_DAYS)
+
+        # Start at overrides to handle edge cases.
         if approval.last_old_suspension:
-            min_suspension_start_at = approval.last_old_suspension.end_at + relativedelta(days=1)
-        # else we set the next min to the date of last accepted job from the pe approval
+            start_at = approval.last_old_suspension.end_at + relativedelta(days=1)
         elif approval.user.last_accepted_job_application.created_from_pe_approval:
-            min_suspension_start_at = today
-
-        is_old_than_max_retroactivity = today - min_suspension_start_at > datetime.timedelta(
-            days=Suspension.MAX_RETROACTIVITY_DURATION_DAYS
-        )
+            start_at = today
 
-        return (
-            today - relativedelta(days=Suspension.MAX_RETROACTIVITY_DURATION_DAYS)
-            if is_old_than_max_retroactivity
-            else min_suspension_start_at
-        )
+        if start_at < start_at_threshold:
+            return start_at_threshold
+        return start_at
 
 
 class ProlongationQuerySet(models.QuerySet):
diff --git a/itou/approvals/tests.py b/itou/approvals/tests.py
index c83b0d15c8..8a14ac3981 100644
--- a/itou/approvals/tests.py
+++ b/itou/approvals/tests.py
@@ -948,23 +948,25 @@ class SuspensionModelTest(TestCase):
 
     def test_clean(self):
         today = timezone.now().date()
-        start_at = timezone.now().date() - relativedelta(months=2)
+        start_at = today - relativedelta(days=Suspension.MAX_RETROACTIVITY_DURATION_DAYS * 2)
         end_at = start_at + relativedelta(months=2)
-        approval = ApprovalFactory(start_at=start_at, end_at=end_at)
-        suspension = SuspensionFactory(approval=approval)
+        approval = ApprovalFactory.build(start_at=start_at, end_at=end_at)
 
-        # test the when suspension is out of boundaries
-        suspension.start_at = start_at - relativedelta(months=1)
+        # Suspension.start_date is too old.
+        suspension = SuspensionFactory.build(approval=approval)
+        suspension.start_at = start_at - relativedelta(days=Suspension.MAX_RETROACTIVITY_DURATION_DAYS + 1)
         with self.assertRaises(ValidationError):
             suspension.clean()
 
-        # the case when end_at < start_at
+        # suspension.end_at < suspension.start_at
+        suspension = SuspensionFactory.build(approval=approval)
         suspension.start_at = start_at
         suspension.end_at = start_at - relativedelta(months=1)
         with self.assertRaises(ValidationError):
             suspension.clean()
 
-        # declare suspension in the future
+        # Suspension.start_at is in the future.
+        suspension = SuspensionFactory.build(approval=approval)
         suspension.start_at = today + relativedelta(days=2)
         suspension.end_at = end_at
         with self.assertRaises(ValidationError):