Hi, apologies if this has already been mentioned quite a lot of posts to go through, but I live in the Languedoc and last year I experienced the 'prioritie a droite' rule. Basically this means if you are on a main road, any car exiting a side road on your right has priority. For a while I wondered why I was being cut up, then I noticed the sign at the entrance of this particular village warning 'you are entering zone priority on the left'. It can happen on roundabouts too, but I must add it's the exception not the norm just something to look out for.
Also whilst on the subject of driving we have noticed the French police have got a lot more strict on drink driving, please don't think you can hide behind your foreign plates! The drink driving rules here are not as leniant as the UK
Apart from the above France is a total joy to drive in, you can go for miles in the countryside without seeing another car, outside the major cities you will rarely see a traffic jam (avoid motorways certain dates in Aug) and they have a sensible speed limit.
Tip - food stops. Don't expect a hot meal on a motorway service station 24 hours. The French eat en masse and lunch is 12 - 2. be warned!
One last tip - yes the N roads are picturesque and free but if you have a great distance to cover just take the autoroute. Or be selective - we find the scenery in the north quite boring so often motorway the first half then take the N roads when there's something worth seeing, ie rivers, vineyards etc
Happy to answer any questions! We live near Beziers in the Languedoc