Take care ! I've always thought the French autoroute speed cameras would not 'flash' unless you were exceeding the 'solo car' limit so no problem towing. Now, however, the toll both cameras can distinguish between Class 1 and Class 2 ( solo or caravan) so maybe the speed cameras can do the same ? However, 55 mph equivalent on dual or autoroute ain't too bad a speed to get there in a relaxed manner, so no real problem.
Do however, watch urban speed limits and read up on the rules that pedestrians have absoulte priority in some urban situations. From very recent experience mini roundabouts are growing like champignons (mushrooms) around towns and it's ofter better to get on the autoroute round big cities and pay the tolls.
(I can't spell in English either)