Hi Stéphane,
About the French locale, I made an attempt to fix this, and when I tested it, it seemed to worked. But I still get some reports that I interpret as locale problems so I'm not sure about the current state.
Anyway, what I first tried was to set the locale before starting the development environment, so if you look in $pwr_exe/wb_start.sh LC_TIME and LC_NUMERIC is set here. Then I discovered that gtk_init(), the init function of the graphical toolkit, modifies the locale, so if you look in wb/exe/wb/gtk/wb_gtk.cpp it is also set here in the main routine after the gtk_init() call. The same you will find for rt_xtt in xtt/exe/rt_xtt/gtk/rt_xtt_gtk.cpp.
/Claes