diff --git a/htdocs/public/payment/newpayment.php b/htdocs/public/payment/newpayment.php
index 79104817e77..144506ab7b6 100644
--- a/htdocs/public/payment/newpayment.php
+++ b/htdocs/public/payment/newpayment.php
@@ -1039,6 +1039,7 @@ if ($source == 'order') {
 		$amount = price2num($amount);
 	}
 
+	$tag = '';
 	if (GETPOST('fulltag', 'alpha')) {
 		$fulltag = GETPOST('fulltag', 'alpha');
 	} else {