To get the best rates and save up to 50%, one should always make rental car arrangements before coming to France. I have used Auto Europe, Avis, and Holiday Auto as well as Kemwel
and been happy with all four. I have also used Budget, but wasn't 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 Citroens, 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 you like minivans, then try 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 recently. Try Travelocity and other travel sites to check on rental car rates.
I always think about booking with two companies (assuming they don't charge until you actually pick up the rental) to avoid incredibly long lines at one rental car company when the company next one has no line.- Narayan Sengupta