I do use Autoeurope and highly recommend it. Their prices are good (I usually go to the company website and others to compare). You do pay for your rental up front, but it is fully refundable until 48 hours before picking up. I have cancelled before, and my CC was refunded quickly. They have a 24 hours helpline, and I have had to use it. Suffice it to say that I am not sure I could have made it out of the rental car agency with out paying more if they had not been available.
I have been renting cars in Europe for over 20 years, and I have seen some changes. I used to use a travel insurance policy to cover the car rental, but have found some companies no longer will accept 3rd party insurance. The problem I had was the rental agency in London would not let me have the car without verifying my insurance, and then would not accept it. Autoeurope talked to them and then told me to present my Mastercard for insurance. Which brings me to my next point:
Some credit cards can provide coverage. Be sure and check that you have one that does. Then be sure and research what is required by the rental place. Autoeurope usually warns you about this and may provide some information, but do your own due diligence. Last time I tried using a CC, Hertz required a letter from the CC bank written within the last 90 days that stated my name and information and verified coverage.
After a couple of stressful rentals trying to be sure I had insurance, I started buying the insurance through Autoeurope. (full coverage, no deductible).
Lastly, I rent early and then monitor prices through the Autoeurope web site. If the price goes down, I call them and they modify my rental. This has happened a few times. However, it has also happened that I got the best price by reserving early.
As for renting in France, I did ten years ago with a different drop off and pick up location. There was no extra fee at that time, but that was a long time ago. If there is an extra fee, Autoeurope will inform you of what it is before finalizing your rental.