What a great gift!!!!!
I think should look for things that scream France...
like maybe a black beret, eiffle tower key chain, French fries (if you wanted to be funny), croissants, a pictures of France, a mini French flag, a picture of Napoleon (again would be funny), a map of France (check traveling agency's), a French maid costume (something you both can enjoy
), wine, banquettes, take a walk around the imports section in your grocery store I'm sure you'll find something...
Have fun in France... Au' Revoir!!