diff --git a/CONTRIBUTING.md b/CONTRIBUTING.md
index d44705b41..58439dd8f 100644
--- a/CONTRIBUTING.md
+++ b/CONTRIBUTING.md
@@ -27,11 +27,14 @@ If you have an idea you're sure would benefit to all of iTop users, you may
 [create a corresponding ticket](https://sourceforge.net/p/itop/tickets/new/) to submit it, but be warned that there are lots of good 
 reasons to refuse such changes.
 
-### 📄 License
+### 📄 License and copyright
 iTop is distributed under the AGPL-3.0 license (see the [license.txt] file),
 your code must comply with this license.
 
-If you want to use another license, you may [create an extension][wiki new ext].
+Combodo has the copyright on each and every source file in the iTop repository: please do not modify the existing file copyrights.  
+Anyhow, you are encouraged to signal your contribution by the mean of `@author` annotations.
+
+If you want to use another license or keep the code ownership (copyright), you may [create an extension][wiki new ext].
 
 [license.txt]: https://github.com/Combodo/iTop/blob/develop/license.txt
 [wiki new ext]: https://www.itophub.io/wiki/page?id=latest%3Acustomization%3Astart#by_writing_your_own_extension