diff --git a/classes/Group.php b/classes/Group.php
index 42ae01e15..75abcad44 100644
--- a/classes/Group.php
+++ b/classes/Group.php
@@ -112,12 +112,12 @@ class GroupCore extends ObjectModel
 
 	public static function getReduction($id_customer = null)
 	{
-		if (!isset(self::$_cacheReduction['customer'][(int)$id_customer]))
+		if (!isset(self::$cache_reduction['customer'][(int)$id_customer]))
         {
             $id_group = $id_customer ? Customer::getDefaultGroupId((int)$id_customer) : (int)Configuration::get('PS_CUSTOMER_GROUP');
-			self::$_cacheReduction['customer'][(int)$id_customer] = Group::getReductionByIdGroup($id_group);
+			self::$cache_reduction['customer'][(int)$id_customer] = Group::getReductionByIdGroup($id_group);
         }
-		return self::$_cacheReduction['customer'][(int)$id_customer];
+		return self::$cache_reduction['customer'][(int)$id_customer];
 	}
 
 	public static function getReductionByIdGroup($id_group)