Sounds like a great trip. My rental car experience in France is limited to walking into an Avis office, so I can’t help there, except I would try EuropaCar in addition to the usual options and I ‘ve heard that you usually get a better deal booking in advance instead of on the spot rental.

My drive trips in France — Normandy if you’re interested in the WWII stuff and other sites. Easy driving conditions, easier to work out and get to the specific things you want to see. Rental car offices are conveniently located near train station in several cities so you can take advantage of the ultra high speed trains from Paris to get there.

I also had a car when I spent two weeks in a tiny village “above the Riviera” in the Alpes Maritime. It was wonderful to be able to get to less crowded beaches, more art museums and for a “living there” as opposed to visiting life style. It was more difficult than Normandy in terms of driving conditions (narrow mountain roads, very aggressive local drivers, lessanymore confusing signing) but greatly scenic and overall thrilling. It’s not for the faint of heart. LA and major US cities are laid back in terms of driving style by comparison.

Look at buying the spiral bound set of Michlin maps….