diff --git a/htdocs/compta/facture/class/facture.class.php b/htdocs/compta/facture/class/facture.class.php
index 79242f5e608..b051a687600 100644
--- a/htdocs/compta/facture/class/facture.class.php
+++ b/htdocs/compta/facture/class/facture.class.php
@@ -72,6 +72,11 @@ class Facture extends CommonInvoice
 	 */
 	public $element = 'facture';
 
+	/**
+	 * @var string Prefix used to build trigger event names in generic CommonObject methods (BILL_MODIFY, ...)
+	 */
+	public $TRIGGER_PREFIX = 'BILL';
+
 	/**
 	 * @var string Name of table without prefix where object is stored
 	 */