I rented a Hertz car in October for 12 days. We had a tiny car reserved which was upgraded NC without even asking. There was a small line on the condition report for the right rear door. Turned out to be quite a lot of damage, although the door worked OK.
We messed up and brought the car back about half full with a tire going flat which I told the counter guy about.
The counter was totally great to deal with on both ends of the ride. The turn-in there is in a garage and there's no one to inspect the car when you leave it.
Nevertheless, the only final bill was for the fuel and they DIDN'T take a cheap shot at me about the damage or the tire.
The whole experience was a good one. In the US, I'm an Emerald Club user and probably will stay one, but I'd recommend Hertz in Paris very highly. A good experience. Fair rates too.
My only other car experience recently was EuropeCar in Spain which was a major ripoff PLUS we had to fight them over some non-existent damage which they charged a few weeks after we turned the car in. Our c/c company (Capital One) got them to reverse it.