I am looking for advice on the subject of GPS, am renting a car in southern France? Buy one here (US), do they rent them there, etc?
Some car rental companies have them available in their rental cars. You could also buy one here, but you'd also need to buy the maps for Europe/France, which can be pricey.
If you will be taking a couple of European trips per year, then I would suggest that you think about buying one and purchasing the appropriate maps. If you will be taking one trip per year or less, than I would suggest just renting it with the car. One thing that we learned with our Nissan rental car was that it got confused with round-abouts. This could have been a quirk with the Nissan system, but I thought I would pass this along. If we had to make a "left turn" at the round-about, when we got to the top of the round-about, the GPS thought we went past the round-about, so it calculated a new route, which totally gummed things up. After a while, we learned to just follow the original path thru the round-about and everything was fine.