Thank you for your answer. However I dropped the idea of trying to
install a different VNC server, since the VNC server I'm using is the
standard one installed by default on Mac OS X. Also, I found that a
strangely quite unknown remote access program, Remote HD, that has no
problems with the french keyboard and the standard Mac OS X VNC
server, just like Mocha VNC, so I guess pointing towards the VNC
server would not be the unique possible answer. Regards.