diff --git a/htdocs/product/class/productcustomerprice.class.php b/htdocs/product/class/productcustomerprice.class.php
index 49386e8a379..c18d09614e6 100644
--- a/htdocs/product/class/productcustomerprice.class.php
+++ b/htdocs/product/class/productcustomerprice.class.php
@@ -690,7 +690,7 @@ class Productcustomerprice extends CommonObject
 		$sql .= " tms=".(dol_strlen($this->tms) != 0 ? "'".$this->db->idate($this->tms)."'" : 'null').",";
 		$sql .= " fk_product=".(isset($this->fk_product) ? $this->fk_product : "null").",";
 		$sql .= " fk_soc=".(isset($this->fk_soc) ? $this->fk_soc : "null").",";
-		$sql .= " ref_customer=".(isset($this->ref_customer) ? $this->ref_customer : "null").",";
+		$sql .= " ref_customer=".(isset($this->ref_customer) ? "'" . $this->db->escape($this->ref_customer) . "'" : "null").",";
 		$sql .= " price=".(isset($this->price) ? $this->price : "null").",";
 		$sql .= " price_ttc=".(isset($this->price_ttc) ? $this->price_ttc : "null").",";
 		$sql .= " price_min=".(isset($this->price_min) ? $this->price_min : "null").",";