diff --git a/DCO b/DCO
new file mode 100644
index 00000000000..d54f007a8c5
--- /dev/null
+++ b/DCO
@@ -0,0 +1,34 @@
+Developer Certificate of Origin
+Version 1.1
+
+Copyright (C) 2002 - Today, The Dolibarr team and its contributors.
+
+Everyone is permitted to copy and distribute verbatim copies of this
+license document, but changing it is not allowed.
+
+
+Developer's Certificate of Origin 1.1
+
+By making a contribution to this project, I certify that:
+
+(a) The contribution was created in whole or in part by me and I
+    have the right to submit it under the open source license
+    indicated in the file; or
+
+(b) The contribution is based upon previous work that, to the best
+    of my knowledge, is covered under an appropriate open source
+    license and I have the right under that license to submit that
+    work with modifications, whether created in whole or in part
+    by me, under the same open source license (unless I am
+    permitted to submit under a different license), as indicated
+    in the file; or
+
+(c) The contribution was provided directly to me by some other
+    person who certified (a), (b) or (c) and I have not modified
+    it.
+
+(d) I understand and agree that this project and the contribution
+    are public and that a record of the contribution (including all
+    personal information I submit with it, including my sign-off) is
+    maintained indefinitely and may be redistributed consistent with
+    this project or the open source license(s) involved.
diff --git a/htdocs/public/payment/newpayment.php b/htdocs/public/payment/newpayment.php
index 1fa873d3fc8..ce835aacbc7 100644
--- a/htdocs/public/payment/newpayment.php
+++ b/htdocs/public/payment/newpayment.php
@@ -1038,7 +1038,7 @@ if ($source == 'invoice') {
 
 	if ($action != 'dopayment') { // Do not change amount if we just click on first dopayment
 		$amount = price2num($invoice->total_ttc - ($invoice->getSommePaiement() + $invoice->getSumCreditNotesUsed() + $invoice->getSumDepositsUsed()));
-		if (GETPOST("amount", 'int')) {
+		if (GETPOST("amount", 'alpha')) {
 			$amount = GETPOST("amount", 'alpha');
 		}
 		$amount = price2num($amount);