About ten-fifteen years ago we did the same thing. Flew into CDG, rented a car through Auto Europe, and drove down the Loire Valley to Avignon and Arles, through Marseille along the coast and the Corniche highway to Monte Carlo where we turned around and headed back, but not on the same roads. For the most part, we stayed clear of the main highways except returning to Paris. I arranged for lodgings on alternate nights only so we could be somewhat free of over scheduling. Had no problem. Coming into St Tropez, we were on what looked to be a paved road which became a dirt road which became a path. About the time we were about ready to back out umpty ump miles (my husband swearing at me for getting us into this!), turned out we were back on a newly paved road.

Anyway, we came back to the airport, dumped the car and went into Paris afor the second third of the trip. It worked for us. No problems with driving. Road signs were in French but with pix. Also, if you ever taken Latin, or a Romance language, you can figure them out. We did and we're not too bright with languages.

Good luck to you in planning - and doing! Jo, still stuck in Sunnyvale.