Hi unSpawn !
Thanks for the hint and sorry the delay. I was busy at work and just now I had some time to play with my system.
Yes, you're right. In FC5 the file is /etc/gdm/PostSession/Default which is executed for every user at exit of the window manager.
I just had to add some code to execute a user script .
Code:
if [ -x ${HOME}/.postsession ]; then
${HOME}/.postsession
fi
Thank you !