One should always make rental car arrangements before coming to France. Doing so means much more reasonable rates and savings of
probably, on average, 50%. Here is the info on the rental cars. I have used Auto Europe, Avis, and Holiday Auto as well as Kemwel
and have been happy with all four. I have also used Budget, but haven't been all that impressed. They will usually match the lowest
rates of one another if you tell them that you've found a great rate elsewhere.
For rental cars, if you're into Citroen's, there used to be a rental car company named Citer which used to offer nothing but Citroen's, but I think that's now been bought by National. If it's a minivan you desire, then look into the Renault Espace. The Peugeot 407 is comfortable and big enough for four or five passengers. In any case, it is just about the size of a BMW 5 or possibly slightly smaller. Of course, you can also get a lot of great German and Italian cars as well as even a Seat (Spanish company owned by and based on Volkswagen platforms) or two. If it's a sedan, then the Peugeot 607 or the latest Citroen C5 flagship should be good in spite of how bland the C5 is compared to grand Citroens of the past. They are both going to be between the size of a BMW 5 Series and BMW 7 Series. Diesel fuel is easy to come by and it's much cheaper too. So between the better mileage and lower price, your per kilometer price using diesel may be around 50 to 60 % of what a gas/fuel-injected car would cost. And the turbo-diesels have good torque to get you running quickly. Make sure your insurance covers you in France.
I used to like Europe by Car the best. I haven't used any of the companies listed on the page in the last few years other than to rent them here in the US. You can also go to Travelocity and other travel sites to check on rental car rates.
That said, one thing that I have never done, but wish that I had is to book with two companies (assuming they don't charge until you actually pick up the rental) to avoid standing in a line that is one hour long at the rental car company I have booked with when the company right next to it has no line.- Narayan Sengupta