Andreas
Please inform your "kind" colleague, that if they intend to bag Commons in future, they should ensure that their own house is in order first; for I now have the sad duty to inform you that they have used images from Commons with scant regard for licencing, and I have made a note of this on the image concerned.
http://commons.wikimedia.org/wiki/File_talk:Road_sign_Homs-Palmyra-Baghdad.j...
The lesson? Before accusing others of violating copyright (i.e. Commons) one should stop and think twice before they open mouth and insert foot.
Regards,
Russavia