car hire in France

Use Kayak, pick the cheapest, favor Europcar if they're close.

There's no charge for dropping in different cities within the same country.

There's no need for deliberation, the whole thing is a five-minute process.

"There's no charge for dropping in different cities within the same country."

Ed is the guru of travel around here, but this statement is not always true in France. Europcar doesn't charge extra for a one-way in country rental. Hertz wanted to charge €65. Go with Europcar.

I agree with Andrea, Hertz charged me $50 to drop in a different city. That was a rental from Colmar to Chartres; it's possible that some other cities don't have that add'l drop charge. So take that into account when comparing with other rental companies, but they may still be the best deal.

My rental will be Paris-Avignon.

While Europcar doesn't charge an additional drop off fee, they do charge extra to pick up at a train station. That charge was less than the drop off charge for Hertz.

EDIT: I use AutoEurope when I rent cars. They are a consolidator based in Maine. It's easy to call them to ask questions before choosing a rental, and it's easy to change or cancel your car.

Check the rates at AutoEurope. I've rented from them a number of times. Call the 800 number and talk to one of their helper bees. They might be able to find vehicles with no or low drop off fees.

I did the same type trip in June. I rented a car from SIXT leaving Paris and dropped off in Nice. There was a drop off charge but the total rental was less than other companies. I kept checking the rates before the trip and the SIXT rates kept going down and they adjusted them. I always book direct with the rental company rather than using Auto Europe, Europecar or the other resellers. I have never booked a lower rate from a consolidator than booking direct.

I haven't used them, myself; but friends swear by Kemwel. The other consolidator with good reviews is Gemut. I know they, and perhaps other consolidators, will match any price you find.

Clarification: Europcar is a rental company, not a consolidator. Kemwel is now owned by AutoEurope. Kemwel/AutoEurope will adjust prices down too, if lower prices appear. AutoEurope used to be good advocating for the renter in case of a dispute. I've noticed a change in level of service in the past three years or so, but I still use them.
Whatever you do, as a non-EU resident, be sure you rent using .com websites, not .fr, and pay in dollars in order to avoid certain taxes you'd have to pay if you rented locally.

Re advice to rent from .com sites and pay in dollars. Does that work if you are already in France? We don't have set dates, and were planning to rent a car a day or two in advance of when we decided to leave Paris and head south. Will we be able to use the (US-based?) consolidators?

Yes, you can. I've even called AutoEurope's 0800-number, which is for use from France, talked to the agent on duty and rented my car while standing in the EuropCar's office in Montagis, a smaller city between Burgundy and the Loire. I can't remember if I used my cell phone or the agency telephone. The voucher was in the EuropeCar computer within two minutes. However, during Christmas vacation and July/August, in Paris the agencies get low on stock, while outside Paris the agencies may run out of cars. We've run into that several times. You have to keep calling around to find anything if you leave it to the last minute during those periods.

Furthermore, once at Christmas we found the allotment for .com had run out, but .fr still had stock to rent--at the higher price.