diff --git a/htdocs/supplier_proposal/class/supplier_proposal.class.php b/htdocs/supplier_proposal/class/supplier_proposal.class.php
index b022c76d0d8..cf8e712a103 100644
--- a/htdocs/supplier_proposal/class/supplier_proposal.class.php
+++ b/htdocs/supplier_proposal/class/supplier_proposal.class.php
@@ -547,8 +547,8 @@ class SupplierProposal extends CommonObject
 			$this->line->tva_tx = $txtva;
 			$this->line->localtax1_tx = ($total_localtax1 ? $localtaxes_type[1] : 0);
 			$this->line->localtax2_tx = ($total_localtax2 ? $localtaxes_type[3] : 0);
-			$this->line->localtax1_type = $localtaxes_type[0];
-			$this->line->localtax2_type = $localtaxes_type[2];
+			$this->line->localtax1_type = empty($localtaxes_type[0]) ? '' : $localtaxes_type[0];
+			$this->line->localtax2_type = empty($localtaxes_type[2]) ? '' : $localtaxes_type[2];
 			$this->line->fk_product = $fk_product;
 			$this->line->remise_percent = $remise_percent;
 			$this->line->subprice = $pu_ht;
@@ -736,8 +736,8 @@ class SupplierProposal extends CommonObject
 			$this->line->tva_tx = $txtva;
 			$this->line->localtax1_tx		= $txlocaltax1;
 			$this->line->localtax2_tx		= $txlocaltax2;
-			$this->line->localtax1_type		= $localtaxes_type[0];
-			$this->line->localtax2_type		= $localtaxes_type[2];
+			$this->line->localtax1_type		= empty($localtaxes_type[0]) ? '' : $localtaxes_type[0];
+			$this->line->localtax2_type		= empty($localtaxes_type[2]) ? '' : $localtaxes_type[2];
 			$this->line->remise_percent		= $remise_percent;
 			$this->line->subprice			= $pu;
 			$this->line->info_bits			= $info_bits;