diff --git a/models/scop_cotisation_cg_exo.py b/models/scop_cotisation_cg_exo.py
index 031f204d857effc99a0b2884c0a4a631cde40f4d..7f69181bdf21caa98a58f9c68fe928a9f24b00f1 100644
--- a/models/scop_cotisation_cg_exo.py
+++ b/models/scop_cotisation_cg_exo.py
@@ -400,7 +400,7 @@ class ScopCotisationExo(models.Model):
                 exo_line_id = self.exo_line_ids.filtered(lambda l: l.contribution_id.id == inv_type)
 
                 if self.type_exo == 'percent':
-                    exo_amount = round(inv_amount * (1 - exo_line_id.percent / 100), 2)
+                    exo_amount = round(inv_amount * (exo_line_id.percent / 100), 2)
                 elif self.type_exo == 'amount':
                     exo_amount = round(inv_amount - exo_line_id.amount, 2)
                 else: