You've undoubtedly read many an article touting the Parisian pharmacie, and it really is as glorious a place as people say. And those books detailing how French woman have it all figured out? I attribute part of their looking so good as they age to the abundance of high-quality face products that are actually affordable for the average woman; I always be sure to stock up before returning to the US.
But the French pharmacie also holds another item I now cannot return to New York without: papier d'arménie. They are a quite simple product, really; a natural room deodorizer that smells a bit like incense, but more pleasant and is a bit less linger-y. I received a kit (comprised of the papers themselves, a little box to burn them in, and some matches) as a gift, and went on the hunt for replacement papers as soon as I got to Paris this August. You can also buy them online if you're in a real bind and simply cannot make your apartment smell decent without them.