diff --git a/htdocs/admin/facture.php b/htdocs/admin/facture.php
index e993d2c276c..d03dbc1f568 100644
--- a/htdocs/admin/facture.php
+++ b/htdocs/admin/facture.php
@@ -280,6 +280,24 @@ if ($action == 'set_FAC_AUTO_FILLJS')
 	}
 }
 
+if ($action == 'set_INVOICE_CREDIT_NOTE_STANDALONE')
+{
+	$freetext = GETPOST('INVOICE_CREDIT_NOTE_STANDALONE');	// No alpha here, we want exact string
+
+	$res = dolibarr_set_const($db, "INVOICE_CREDIT_NOTE_STANDALONE",$freetext,'chaine',0,'',$conf->entity);
+
+	if (! $res > 0) $error++;
+
+	if (! $error)
+	{
+		setEventMessage($langs->trans("SetupSaved"));
+	}
+	else
+	{
+		setEventMessage($langs->trans("Error"),'errors');
+	}
+}
+
 
 /*
  * View
@@ -750,6 +768,34 @@ print '<input type="submit" class="button" value="'.$langs->trans("Modify").'" /
 print "</td></tr>\n";
 print '</form>';
 
+// Add js auto fill amount on paiement form
+$var=! $var;
+print '<form action="'.$_SERVER["PHP_SELF"].'" method="POST">';
+print '<input type="hidden" name="token" value="'.$_SESSION['newtoken'].'" />';
+print '<input type="hidden" name="action" value="set_FAC_AUTO_FILLJS" />';
+print '<tr '.$bc[$var].'><td>';
+print $langs->trans("JSOnPaimentBill");
+print '</td><td width="60" align="center">';
+print $form->selectyesno("FAC_AUTO_FILLJS",$conf->global->FAC_AUTO_FILLJS,1);
+print '</td><td align="right">';
+print '<input type="submit" class="button" value="'.$langs->trans("Modify").'" />';
+print "</td></tr>\n";
+print '</form>';
+
+// Allow to create credit note not related to an invoice
+$var=! $var;
+print '<form action="'.$_SERVER["PHP_SELF"].'" method="POST">';
+print '<input type="hidden" name="token" value="'.$_SESSION['newtoken'].'" />';
+print '<input type="hidden" name="action" value="set_INVOICE_CREDIT_NOTE_STANDALONE" />';
+print '<tr '.$bc[$var].'><td>';
+print $langs->trans("AllowCreditNoteWithoutRelatedInvoice");
+print '</td><td width="60" align="center">';
+print $form->selectyesno("INVOICE_CREDIT_NOTE_STANDALONE",$conf->global->INVOICE_CREDIT_NOTE_STANDALONE,1);
+print '</td><td align="right">';
+print '<input type="submit" class="button" value="'.$langs->trans("Modify").'" />';
+print "</td></tr>\n";
+print '</form>';
+
 $var=! $var;
 print '<form action="'.$_SERVER["PHP_SELF"].'" method="POST">';
 print '<input type="hidden" name="token" value="'.$_SESSION['newtoken'].'" />';
@@ -774,20 +820,6 @@ print '<input type="submit" class="button" value="'.$langs->trans("Modify").'" /
 print "</td></tr>\n";
 print '</form>';
 
-// Add js auto fill amount on paiement form
-$var=! $var;
-print '<form action="'.$_SERVER["PHP_SELF"].'" method="POST">';
-print '<input type="hidden" name="token" value="'.$_SESSION['newtoken'].'" />';
-print '<input type="hidden" name="action" value="set_FAC_AUTO_FILLJS" />';
-print '<tr '.$bc[$var].'><td>';
-print $langs->trans("JSOnPaimentBill");
-print '</td><td width="60" align="center">';
-print $form->selectyesno("FAC_AUTO_FILLJS",$conf->global->FAC_AUTO_FILLJS,1);
-print '</td><td align="right">';
-print '<input type="submit" class="button" value="'.$langs->trans("Modify").'" />';
-print "</td></tr>\n";
-print '</form>';
-
 print '</table>';
 
 
diff --git a/htdocs/compta/facture.php b/htdocs/compta/facture.php
index a5f7f1e004d..37812dbf413 100644
--- a/htdocs/compta/facture.php
+++ b/htdocs/compta/facture.php
@@ -706,7 +706,8 @@ if (empty($reshook))
 		// Credit note invoice
 		if ($_POST['type'] == Facture::TYPE_CREDIT_NOTE)
 		{
-			if (! ($_POST['fac_avoir'] > 0))
+			$sourceinvoice = GETPOST('fac_avoir');
+			if (! ($sourceinvoice > 0) && empty($conf->global->INVOICE_CREDIT_NOTE_STANDALONE))
 			{
 				$error ++;
 				setEventMessage($langs->trans("ErrorFieldRequired", $langs->transnoentitiesnoconv("CorrectInvoice")), 'errors');
@@ -739,7 +740,7 @@ if (empty($reshook))
 				$object->location_incoterms = GETPOST('location_incoterms', 'alpha');
 
 				// Proprietes particulieres a facture avoir
-				$object->fk_facture_source = $_POST['fac_avoir'];
+				$object->fk_facture_source = $sourceinvoice > 0 ? $sourceinvoice : '';
 				$object->type = Facture::TYPE_CREDIT_NOTE;
 
 				$id = $object->create($user);
@@ -2878,7 +2879,7 @@ else if ($id > 0 || ! empty($ref))
 		$facreplaced->fetch($object->fk_facture_source);
 		print ' (' . $langs->transnoentities("ReplaceInvoice", $facreplaced->getNomUrl(1)) . ')';
 	}
-	if ($object->type == Facture::TYPE_CREDIT_NOTE) {
+	if ($object->type == Facture::TYPE_CREDIT_NOTE && !empty($object->fk_facture_source)) {
 		$facusing = new Facture($db);
 		$facusing->fetch($object->fk_facture_source);
 		print ' (' . $langs->transnoentities("CorrectInvoice", $facusing->getNomUrl(1)) . ')';
diff --git a/htdocs/core/modules/facture/doc/pdf_crabe.modules.php b/htdocs/core/modules/facture/doc/pdf_crabe.modules.php
index aa9fbf65ed2..74d73d5d497 100644
--- a/htdocs/core/modules/facture/doc/pdf_crabe.modules.php
+++ b/htdocs/core/modules/facture/doc/pdf_crabe.modules.php
@@ -1500,7 +1500,7 @@ class pdf_crabe extends ModelePDFFactures
 			$pdf->SetTextColor(0,0,60);
 			$pdf->MultiCell(100, 3, $outputlangs->transnoentities("ReplacementInvoice").' : '.$outputlangs->convToOutputCharset($objectreplaced->ref), '', 'R');
 		}
-		if ($object->type == 2)
+		if ($object->type == 2 && !empty($object->fk_facture_source))
 		{
 			$objectreplaced=new Facture($this->db);
 			$objectreplaced->fetch($object->fk_facture_source);
diff --git a/htdocs/langs/en_US/admin.lang b/htdocs/langs/en_US/admin.lang
index 3bf2d5a14b5..bf1010f767b 100755
--- a/htdocs/langs/en_US/admin.lang
+++ b/htdocs/langs/en_US/admin.lang
@@ -1165,6 +1165,7 @@ CreditNotePDFModules=Credit note document models
 CreditNote=Credit note
 CreditNotes=Credit notes
 ForceInvoiceDate=Force invoice date to validation date
+AllowCreditNoteWithoutRelatedInvoice=Allow to create credit note without a related invoice
 DisableRepeatable=Disable repeatable invoices
 SuggestedPaymentModesIfNotDefinedInInvoice=Suggested payments mode on invoice by default if not defined for invoice
 EnableEditDeleteValidInvoice=Enable the possibility to edit/delete valid invoice with no payment