Been to France 5 times for 4/5 weeks and 3/4 sites at a time, since "07 with an A frame, and never had the slightest problems with les Gendarmes or customs at the docks. We tow a Fiat Multipla on a Brian Cox braked Aframe and, yes, I can reverse with no probs. Dunno" if I"ve just been lucky but, on couple of occasions,I"ve had a chat with Police (French and English) who just seemed interested in how it worked. Did have a couple of "hairy" moments with other drivers not realizing we were "connected" and trying to get between the car and the motorhome and you do have to remember how long you are, that"s where a rearvew camera is essential !
I"m aware that Spanish police are not too keen on them, "tho I think that"s more a case of them being bloody minded and wanting some "fine" money.