you would expect them to be able to call up the french and ask if the pp is genuine. if they suspect the picture has been changed, how would they do this tough?

i guess they could colour-photocopy the thing and send it to the french and they could see and confirm if it matches the picture on their files in their passport systems. provided they actually have the file in a computer system and not sitting somewhere in the physical archives of the prefecture de police. anything is possible.

al