diff --git a/htdocs/admin/supplier_order.php b/htdocs/admin/supplier_order.php
index 808528cdc0a..5eb48b627d4 100644
--- a/htdocs/admin/supplier_order.php
+++ b/htdocs/admin/supplier_order.php
@@ -149,6 +149,7 @@ if ($action == 'updateMask') {
 
 	$res1 = dolibarr_set_const($db, "SUPPLIER_ORDER_FREE_TEXT", $freetext, 'chaine', 0, '', $conf->entity);
 	$res2 = dolibarr_set_const($db, "SUPPLIER_ORDER_3_STEPS_TO_BE_APPROVED", $doubleapproval, 'chaine', 0, '', $conf->entity);
+	$res3 = dolibarr_set_const($db, "FORBID_EDIT_PROJECT_ON_SUPPLIER_ORDER", GETPOST('FORBID_EDIT_PROJECT_ON_SUPPLIER_ORDER', 'int'), 'chaine', 0, '', $conf->entity);
 
 	// TODO We add/delete permission here until permission can have a condition on a global var
 	include_once DOL_DOCUMENT_ROOT.'/core/modules/modFournisseur.class.php';
@@ -532,6 +533,15 @@ if ($conf->reception->enabled) {
 print "</td>\n";
 print "</tr>\n";
 
+// Option
+print '<tr class="oddeven">';
+print '<td>'.$langs->trans("SupplierOrderForbidProjectChange").'</td>';
+print '<td class="center">'.$form->selectyesno('FORBID_EDIT_PROJECT_ON_SUPPLIER_ORDER', $conf->global->FORBID_EDIT_PROJECT_ON_SUPPLIER_ORDER, 1).'</td>';
+print '<td class="center">';
+print '<input type="submit" class="button button-edit" value="'.$langs->trans("Modify").'">';
+print '</td>';
+print '</tr>';
+
 print '</table><br>';
 
 print '</form>';
diff --git a/htdocs/fourn/commande/card.php b/htdocs/fourn/commande/card.php
index 4c8bed6bfe6..cea11eda9bc 100644
--- a/htdocs/fourn/commande/card.php
+++ b/htdocs/fourn/commande/card.php
@@ -144,6 +144,11 @@ $permissiondellink	= $usercancreate; // Used by the include of actions_dellink.i
 $permissiontoedit	= $usercancreate; // Used by the include of actions_lineupdown.inc.php
 $permissiontoadd	= $usercancreate; // Used by the include of actions_addupdatedelete.inc.php
 
+// Project permission
+if (!empty($conf->projet->enabled)) {
+	$caneditproject = empty($conf->global->FORBID_EDIT_PROJECT_ON_SUPPLIER_ORDER) || ($object->statut == CommandeFournisseur::STATUS_DRAFT && preg_match('/^[\(]?PROV/i', $object->ref));
+}
+
 
 /*
  * Actions
@@ -239,7 +244,7 @@ if (empty($reshook)) {
 	}
 
 	// Set project
-	if ($action == 'classin' && $usercancreate) {
+	if ($action == 'classin' && $usercancreate && $caneditproject) {
 		$result = $object->setProject($projectid);
 		if ($result < 0) {
 			setEventMessages($object->error, $object->errors, 'errors');
@@ -1988,7 +1993,7 @@ if ($action == 'create') {
 		$langs->load("projects");
 		$morehtmlref .= '<br>'.$langs->trans('Project').' ';
 		if ($usercancreate) {
-			if ($action != 'classify') {
+			if ($action != 'classify' && $caneditproject) {
 				$morehtmlref .= '<a class="editfielda" href="'.$_SERVER['PHP_SELF'].'?action=classify&token='.newToken().'&id='.$object->id.'">'.img_edit($langs->transnoentitiesnoconv('SetProject')).'</a> : ';
 			}
 			if ($action == 'classify') {
diff --git a/htdocs/langs/en_US/admin.lang b/htdocs/langs/en_US/admin.lang
index def603e653e..6620b3c73ff 100644
--- a/htdocs/langs/en_US/admin.lang
+++ b/htdocs/langs/en_US/admin.lang
@@ -1436,6 +1436,7 @@ OrdersNumberingModules=Orders numbering models
 OrdersModelModule=Order documents models
 FreeLegalTextOnOrders=Free text on orders
 WatermarkOnDraftOrders=Watermark on draft orders (none if empty)
+SupplierOrderForbidProjectChange=Forbid changing the project of a supplier order or a draft which already has a reference
 ShippableOrderIconInList=Add an icon in Orders list which indicate if order is shippable
 BANK_ASK_PAYMENT_BANK_DURING_ORDER=Ask for bank account destination of order
 ##### Interventions #####
diff --git a/htdocs/langs/fr_FR/admin.lang b/htdocs/langs/fr_FR/admin.lang
index 9579e51920d..16279587795 100644
--- a/htdocs/langs/fr_FR/admin.lang
+++ b/htdocs/langs/fr_FR/admin.lang
@@ -1428,6 +1428,7 @@ OrdersNumberingModules=Modèles de numérotation des commandes
 OrdersModelModule=Modèles de document des commandes
 FreeLegalTextOnOrders=Mention complémentaire sur les commandes
 WatermarkOnDraftOrders=Filigrane sur les brouillons de commandes (aucun si vide)
+SupplierOrderForbidProjectChange=Interdire de modifier le projet d'une commande validée (ou en brouillon mais ayant déjà une référence)
 ShippableOrderIconInList=Ajouter une icône dans la liste des commandes qui indique si la commande est expédiable.
 BANK_ASK_PAYMENT_BANK_DURING_ORDER=Demander le compte bancaire cible durant la commande
 ##### Interventions #####