Auto Rental in France

I would book from:
www.autoeurope.com
And select a car from their site from Europcar, Hertz, Avis or Sixt only

No GPS needed ; if you phone will work than so will your phone nav apps like Waze or Google Maps.
For me those are far better than the Garmin type GPS devices for driving.

If you belong to Costco, check their Travel section the prices are less than anywhere.

I usually use Europcar. Lots of locations, less expensive, fine cars, and no in-country dropoff fees.

Using your phone for navigation depends on what kind of international plan you have ... Something to look into beforehand so you don't go home to an unexpected $$$$ phone bill or run through the data on your SIM plan.

I always use Hertz. You can join club for free and get good rates. Data rates will eat you alive on your phone. I bought a GPS with Europe maps and it has worked very well.

We did almost the exact same trip last year. Hertz is who we used. For navigation, get the app Here. I used it everywhere for getting around. The best part of Here is that you load the map for France to your phone. No data required to use it. My phone plan was good however there are some places had no bars in Normandy. Here never missed a beat. When in Paris it was still usable when underground on the metro.

I have almost always gone through Auto Europe, and rented with either Europcar or Hertz.

One important point to mention is that it's highly advisable for each driver listed on the rental form to have an International Drivers Permit, which is used in conjunction with your home DL. These are easily available at any AAA /CAA office for a small fee, and are valid for one year.

I have used Google Maps offline to navigate in France and other parts of Europe. Download the maps ahead of time over Wi-Fi. You can use the maps on your smartphone offline and it will still give you voice directions and will recalibrate if you take a wrong turn. However, be sure to have a power cord and adapter so that you won't lose power (map apps eat up power) and a removable phone mount for the car.

I have always used AutoEurope (a consolidator) and I'm pretty sure the rentals have been through Europcar. Google maps works fine for me in Europe.

I always check the options (Avis, Europcar, Hertz, etc.) and have ended up with Hertz the last two trips to France. I confess, however, I haven't checked Costco. I'll see what they have for my upcoming trip in June.

If you own a GPS of your own, just buy/download the maps for Europe before your trip. It'll work just like back home.
I download Google Maps for offline use in the cities I am in. But the area for each individual map is limited. So I don't find they're useful for driving. They make walking around a city great though—particularly if you've "saved" all your favorite places ahead of time.

Thanks to all for the great info. It is appreciated.

We have used Auto Europe to find good prices and get general info from their knowledgeable agents. We have rented Europcar and been happy with them, except for one time when they sent our car out without enough oil. But overall they have been good, as others have said, and we have used them since. We have reserved a car more recently with Hertz, although we have not taken our trip yet, and their prices etc were good. Also you can get a 10% discount on Hertz, even international, if you are a AAA member.

I always use Hertz. You can join club for free and get good rates. Data rates will eat you alive on your phone. I bought a GPS with Europe maps and it has worked very well.

I've used Hertz/Thtifty a couple of times recently where they have removed the SD card from the navigation system that comes as standard with the car in an effort to force you to rent a separate sat nav at extortionate prices. For me this is completely unacceptable and I will avoid renting from Hertz from now on.

As for using your phone for navigation I've been using Google Maps (without downloading the offline versions) in Spain these last two weeks and barely made a dent in my data plan.

Second Costco