diff --git a/htdocs/eventorganization/conferenceorbooth_list.php b/htdocs/eventorganization/conferenceorbooth_list.php
index c02306ba6be..d72941d2885 100644
--- a/htdocs/eventorganization/conferenceorbooth_list.php
+++ b/htdocs/eventorganization/conferenceorbooth_list.php
@@ -288,7 +288,7 @@ if ($projectid > 0) {
 	$morehtmlref .= '</div>';
 
 	// Define a complementary filter for search of next/prev ref.
-	if (!$user->rights->project->all->lire) {
+	if (empty($user->rights->project->all->lire)) {
 		$objectsListId = $project->getProjectsAuthorizedForUser($user, 0, 0);
 		$project->next_prev_filter = " rowid IN (".$db->sanitize(count($objectsListId) ? join(',', array_keys($objectsListId)) : '0').")";
 	}