diff --git a/htdocs/core/lib/functions.lib.php b/htdocs/core/lib/functions.lib.php
index bace4411184..4dc1f7251c1 100644
--- a/htdocs/core/lib/functions.lib.php
+++ b/htdocs/core/lib/functions.lib.php
@@ -5811,9 +5811,12 @@ function get_default_tva(Societe $thirdparty_seller, Societe $thirdparty_buyer,
 	if (($seller_in_cee && $buyer_in_cee)) {
 		$isacompany = $thirdparty_buyer->isACompany();
 		if ($isacompany) {
-			if (!empty($conf->global->MAIN_USE_VAT_OF_PRODUCT_FOR_COMPANIES_IN_EEC_WITH_INVALID_VAT_ID) && !isValidVATID($thirdparty_buyer)) {
-				//print 'VATRULE 6';
-				return get_product_vat_for_country($idprod, $thirdparty_seller, $idprodfournprice);
+			if (!empty($conf->global->MAIN_USE_VAT_OF_PRODUCT_FOR_COMPANIES_IN_EEC_WITH_INVALID_VAT_ID)) {
+				require_once DOL_DOCUMENT_ROOT.'/core/lib/functions2.lib.php';
+				if (!isValidVATID($thirdparty_buyer)) {
+					//print 'VATRULE 6';
+					return get_product_vat_for_country($idprod, $thirdparty_seller, $idprodfournprice);
+				}
 			}
 			//print 'VATRULE 3';
 			return 0;