diff --git a/htdocs/product/class/product.class.php b/htdocs/product/class/product.class.php
index bd3cf69c86a..6fd09ed9723 100644
--- a/htdocs/product/class/product.class.php
+++ b/htdocs/product/class/product.class.php
@@ -1690,7 +1690,7 @@ class Product extends CommonObject
 		$testExit = array('multiprices','multiprices_ttc','multiprices_base_type','multiprices_min','multiprices_min_ttc','multiprices_tva_tx','multiprices_recuperableonly');
 
 		foreach ($testExit as $field) {
-			if (!isset($this->$field[$level])) {
+			if (!isset($this->{$field}[$level])) {
 				return array();
 			}
 		}