One thing I've been advised previously about car rentals in France, is to check for damage thoroughly before leaving the rental place. Even small chips need to be noted properly as they tend to look closely at the car upon return.
Something to remember. I've never rented there, so can't fully ascertain the validity of this comment though.
you are correct in what you've been told. In 2004 we rented a car from CDG for 14 days.
Luckily I had been pre-warned about their methods and when I picked the car up I spent about 5 minutes going over it and making comments on the sheet.
We returned the car very early in the morning when it was dark and the agent went over the car with a torch. He made a couple of comments about scratches underneath the front (luckily I had been told about this too) and I told him that there was nowhere on the sheet to indicate damage underneath and that I made a comment on the bottom when I picked the car up. He was happy with that and we were on our way.
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.