I think you answered your own question. I am certainly no expert at voies metriques, but I have seen photos of such trains with and without what appears to be brake/guards vans. For example, here's a passenger train with what appears to be a brake or guards van at the end:
Some french lines also seem to have had an aversion to running locomotives in "reverse", which also adds another twist, unless you run a tramway or "bicabine" style loco.
"It is one of the happiest characteristics
of this glorious country that official utterances are invariably
regarded as unanswerable."
-Sir Joseph Porter, First Lord of the Admiralty (HMS Pinafore)