Not just France where they can try and rip you off.
I always take copious "before and after" photos of the car (and the instrument panel showing km's, etc) with my digital camera, and haven't had a problem so far. I'd recommend this to everyone, as it's a very cheap way of moving the odds a little way in your favour. Obviously not foolproof, but every little helps, especially if you have a good lawyer.
As for good car rental companies, you can't really go past the biggies (Hertz and Avis), but I would recommend that you take out Gold/Preferred membership first.
As an alternative to these companies, I would recommend
http://www.rentacar-worldwide.com/ ,which I have used many times. They are very well priced in continental Europe and generally use the Alamo car rental company.