Driving in France - Some considerations
We drove all over France a few years back and it wasn't too big a deal but there were some things I prepped on before trip and learned also along the way.
Most car rentals are for standard / manual transmission so unless you're ok with shifting a stick; ask for an automatic but it will cost more and may not be available depending where you pickup your rental. Insurance coverage is waay lower than U.S. so I'd recommend you opt for insurance. Sure, your credit card may offer some damage/collission coverage but it's a super hassle to get a claim resolved overseas (from people I know who've had to) and thanks to EU laws, there's not the same wild west personal injury atmosphere that we have in the U.S., hence lawyers generally don't get to split settlements with clients as they do in U.S.
Also -- be prepared for tolls on major highways. We drove from Toulouse in South France all the way up the coast to Honfleur and back to Paris and paid our share of tolls but the highways are superb and people drove the speed limit 99% of the time due to radar / speed camera zones (which are usually marked). If you speed, you'll get a fine in the mail a week or two later and the amount will be deducted by the rental agency.
ROUNDABOUTS -- this is the biggest area of confusion for Americans -- we had friends wreck their rental because they didn't understand how to merge in / out of a roundabout and they got distracted by the GPS voice direction and vague road signage. You may want to sharpen your knowledge about this and check out some driving tips on YouTube.
GPS in cars is a little different in France (at the time we rented) it works pretty well but not as user friendly in U.S. as when you key in a destination....you'll likely scroll through a half-dozen or more places with similiar names. We didn't realize that some things on a map are abbreviated sometimes and leave out middle names. Also anything with a "..sur-mer " is likely to have a ton of towns so be advised. We used our cell GPS / Google Maps as a backup.
Be aware of parking places as not all places are legal and even some "car parks" were hard to get in and out of. In Caen we learned we could park free on the street outside the hotel during limited hours like overnight but move before 7am or we'd get ticketed. The underground garage was a bear to get in and out of even in our small Renault as they squeeze as many parking slots as they can in those.
And do get familiar with traffic signage as it's quite different than U.S. Some things like "No Entry" symbols, etc, can sneak up on you in a flash and you're going down the wrong way in a tiny street. Normandy is pretty easy to get around but if you are on a local / rural route ... always be vigilant as some locals will pass on curves and do things that defy logic and good safety practices. There were a couple times around La Rochelle area that gave me a startle. We were driving on a narrow roadway in the country and all of a sudden a mass of bicyclists came heading towards really fast. I pulled over and waited for them to pass as it was some type of competition.
Here's a link to road signage:
http://www.drive-france.com/faqs/french-road-signs/
). As I recall, our biggest issue was paying on the toll roads because payment methods were not standardized, but I think it's much better now. 
