diff --git a/htdocs/projet/list.php b/htdocs/projet/list.php
index 86f1c2ffcad..45ab6348aa9 100644
--- a/htdocs/projet/list.php
+++ b/htdocs/projet/list.php
@@ -5,6 +5,7 @@
  * Copyright (C) 2005-2010 Regis Houssin        <regis.houssin@capnetworks.com>
  * Copyright (C) 2013      Cédric Salvador      <csalvador@gpcsolutions.fr>
  * Copyright (C) 2015 	   Claudio Aschieri     <c.aschieri@19.coop>
+ * Copyright (C) 2019 	   Juanjo Menent	    <jmenent@2byte.es>
  *
  * This program is free software; you can redistribute it and/or modify
  * it under the terms of the GNU General Public License as published by
@@ -69,9 +70,9 @@ $pagenext = $page + 1;
 
 $search_all=GETPOST('search_all', 'alphanohtml');
 $search_categ=GETPOST("search_categ",'alpha');
-$search_ref=GETPOST("search_ref");
-$search_label=GETPOST("search_label");
-$search_societe=GETPOST("search_societe");
+$search_ref=GETPOST("search_ref",'alpha');
+$search_label=GETPOST("search_label",'alpha');
+$search_societe=GETPOST("search_societe",'alpha');
 $search_year=GETPOST("search_year");
 $search_status=GETPOST("search_status",'int');
 $search_opp_status=GETPOST("search_opp_status",'alpha');