diff --git a/htdocs/core/lib/functions2.lib.php b/htdocs/core/lib/functions2.lib.php
index 9c77729ac5a..2b31296ad7a 100644
--- a/htdocs/core/lib/functions2.lib.php
+++ b/htdocs/core/lib/functions2.lib.php
@@ -814,7 +814,7 @@ function get_next_value($db,$mask,$table,$field,$where='',$objsoc='',$date='',$m
     //print "masktri=".$masktri." maskcounter=".$maskcounter." maskraz=".$maskraz." maskoffset=".$maskoffset."<br>\n";
 
     // Define $sqlstring
-    $posnumstart=strrpos($maskwithnocode,$maskcounter);	// Pos of counter in final string (from 0 to ...)
+    $posnumstart=mb_strrpos($maskwithnocode,$maskcounter, 'UTF-8');	// Pos of counter in final string (from 0 to ...)
     if ($posnumstart < 0) return 'ErrorBadMaskFailedToLocatePosOfSequence';
     $sqlstring='SUBSTRING('.$field.', '.($posnumstart+1).', '.dol_strlen($maskcounter).')';