Driving in France...
First, Don't Worry!! Its wonderful!
There are a few rules to follow, but after thousands of miles I have never been stopped, never had a problem, always loved it and never wanted to come back!! Just drive sensibly, take your time and you'll be fine.
A good tip is to drape your hi-vis vests over the front seat-backs, so the cops can see them when they drive past.. That way they won't stop you to ask for them!
You definitely need a warning triangle(2 if you go to Spain), a first-aid kit, spare bulbs, fire extinguisher and soon you will need a personal breathalyser (but its not compulsory yet, and they'll be available for a few Euros in any French supermarket).
As someone said, park up, sleep, cook, whatever, but don't set up camp with awnings, tables, BBQ's etc by the roadside or in the Aires.. (common sense, really..)
There's a lovely Aire at the village of Verteuil-sur-Charente, south of Poitiers. Immaculate, free, beautiful park with clean loos etc.. Stroll into the village (300metres) and visit the Dixie Bar... 50/50 French/English clientele and staff, good food, music, company....
We'll be back as soon as we can!
Enjoy!!