Snow in France is a nightmare, the major roads grind to a standstill as the lorries by law have to stop they then take up residence in the slow lane of all dual carriage ways which leaves just one lane open which inevitably gets blocked, Christmas 09 I towed a 2.5 ton trailer down to Spain, got directed off the motorway into a small town and then spent the next 3 hours trying to find a way out that was not blocked, spent all the following day in low range 4 wheel drive going across country to avoid the traffic jams, which worked.
Personally if I had to make the journey again across France in snow I would get on a toll road as soon as I got off the ferry and not get off until I`m in Spain as these are the only roads that are continuously gritted, mind the service areas as these are not gritted- found that out the hard way on a motorbike. only cross the boarder at the coast I prefer the Med I just head for Perpagnan.
Good Luck
Personally if I had to make the journey again across France in snow I would get on a toll road as soon as I got off the ferry and not get off until I`m in Spain as these are the only roads that are continuously gritted, mind the service areas as these are not gritted- found that out the hard way on a motorbike. only cross the boarder at the coast I prefer the Med I just head for Perpagnan.
Good Luck