Agree with Phil. No need to worry about it as the roads are much nicer and quieter than our congested and pot-hole ridden tarmac..
The French also understand lane discipline so you rarely come across middle or outside lane hoggers, slow moving vehicles on single lane roads will pull in to the side to let you past unlike the 40 everywhere brigade over here who will try there best to block you.
Look out for cars flashing you as they also like to warn drivers about speed traps up ahead. Like the UK speed traps they are normally set up where road works are going on so pay attention to changes in the speed limits on m'ways and also when going through villages and towns.
We did 10 days back in June driving from Caen-LaRochelle-Bordeaux-Biarritz-StEmillion-LeMans-Home and had no problems what so ever apart from setting off a few fixed speed cameras which we have heard nothing about since.
Lovely place and off back next year