diff --git a/models/acc_operation.py b/models/acc_operation.py
index 156181b85971652f900913957384858458b275d8..6a57593a0b7a7783afee0da9ccafbf5be9b708ae 100644
--- a/models/acc_operation.py
+++ b/models/acc_operation.py
@@ -259,24 +259,6 @@ class AccOperation(models.Model):
 
         return date_start, date_end
 
-    def get_first_day(self):
-        """
-        Fonction retournant la première date où des données ont été enregistrées.
-        :return: une date
-        """
-
-        # Get last date slot recorded
-        first_record = self.env["acc.enedis.cdc"].sudo().search(
-            [
-                ("acc_operation_id", "in", self.ids),
-            ],
-            limit=1,
-            order="date_slot ASC",
-        )
-
-        date_min = first_record.date_slot
-        return date_min
-
     def get_step_from_date(self, date_start, date_end, scale=None):
         """
         Fonction retournant le pas des courbes en fonction de 2 dates.
@@ -646,7 +628,8 @@ class AccOperation(models.Model):
         last_record = self.get_the_last_day()
         date_deb, date_max = self.get_last_day("day", last_record)
         date_max = date_max.strftime("%d/%m/%Y")
-        date_min = self.get_first_day()
+        date_min = self.date_start_contract
+
         date_min = date_min.strftime("%d/%m/%Y")
         result_graph.update(
             {