diff --git a/htdocs/core/modules/facture/mod_facture_mercure.php b/htdocs/core/modules/facture/mod_facture_mercure.php
index 321741ea8a0..1e96c32129a 100644
--- a/htdocs/core/modules/facture/mod_facture_mercure.php
+++ b/htdocs/core/modules/facture/mod_facture_mercure.php
@@ -77,7 +77,7 @@ class mod_facture_mercure extends ModeleNumRefFactures
 
 		// Setting the prefix
 		$texte .= '<tr><td><span class="opacitymedium">'.$langs->trans("Mask").' ('.$langs->trans("InvoiceStandard").'):</span></td>';
-		$texte .= '<td class="right">'.$form->textwithpicto('<input type="text" class="flat minwidth175" name="maskinvoice" value="'.$conf->global->FACTURE_MERCURE_MASK_INVOICE.'">', $tooltip, 1, 1).'</td>';
+		$texte .= '<td class="right">'.$form->textwithpicto('<input type="text" class="flat minwidth175" name="maskinvoice" value="FACTURE_MERCURE_MASK_INVOICE">', $tooltip, 1, 1).'</td>';
 
 		$texte .= '<td class="left" rowspan="3">&nbsp; <input type="submit" class="button button-edit" name="Button"value="'.$langs->trans("Modify").'"></td>';