diff --git a/htdocs/expensereport/card.php b/htdocs/expensereport/card.php
index f70982fd429..63abda22fed 100644
--- a/htdocs/expensereport/card.php
+++ b/htdocs/expensereport/card.php
@@ -216,7 +216,7 @@ if (empty($reshook))
     	    if ($ret < 0) $error++;
     	}
 
-    	if ($object->periode_existe($fuser,$object->date_debut,$object->date_fin))
+    	if (empty($conf->global->EXPENSEREPORT_ALLOW_OVERLAPPING_PERIODS) && $object->periode_existe($fuser,$object->date_debut,$object->date_fin))
     	{
     		$error++;
     		setEventMessages($langs->trans("ErrorDoubleDeclaration"), null, 'errors');