Using our USA GPS in France and Belgium

Take your own, you'll be shocked at the added cost per day of a GPS to a rental car. You can also preload destinations at home and be ready to hit the road. We used ours sparingly for foot travel,in narrow streets or with tall buildings around the GPS would sometimes get confused on which direction we were walking. One thing we really liked was having our accomodation's directions for returning after an outing. Makes life easy!

You may consider as well if your GPS is worth getting the maps, or buy new.

I know my Tom Tom is old enough that given the cost of European maps and concerns about memory, that I would just buy new to upgrade, maybe even get the Europe maps included.

Take your own GPS or buy a new one with European maps already loaded. We preloaded salient addresses into it and driving was a breeze. WE also had a Michelin road map for those times when the GPS wanted to take us down a narrow back road instead of staying on the 4 lane highway. We stayed in the Norman countryside, with no address, so we used Google maps to save the map coordinates (down at the bottom left of the screen)of the rural farmhouse into the GPS and drove right to it. The car rental lot was down a back alley in Caen so I saved the position of the alley entry into the GPS as we departed and it took us right back to it in a driving (no pun) rainstorm a week later.
For foot travel we take a small compass and a city map. The GPS works intermittantly in most cities like Paris or London but the map and compass work much better.

I always suggest a GPS you are familiar with rather than trying to learn an unfamiliar GPS on the road.

The europe chip was going to be $160 FYI