I had Knoppix 7.4 installed by Universal-USB-Installer (UI) and UI places its own syslinux.cfg out of sight in a sub-folder.
Anyway, I did a fresh install with K's own Flash Install and created a new persistent img.
With the cheatcodes for keyboard=fr and tz=Europe/Paris in the thrre ". cfg" files concerned, AND the change in "/etc/adjtime", I now have everything working correctly (no need for Keyboard Layout Handler).
No doubt, other Knoppix users suffered from similar hiccups.
Thanks again.