It's not quite off the beaten path, but I always wanted to see the canadian memorial in Vimy.

You should go to Oradour-sur-Glane. I have never been but I would like to one day.

Vichy might be a bit creepy.

I went to the Museum of the Deportation and Resistance in Lyon. It was really informative. The exhibit of the boxcar was surreal. It was also the headquarters of Klaus Barbie, the SS head for France.

I also really liked the Jean Moulin museum in Paris. I'm partial to Moulin though.