The plane-tree shaded sidewalks along both banks of the Seine are a perfect place to browse the vendors who set up shop almost daily (with a great deal of them appearing on the weekends). Books, movies, posters, post cards, sheet music. It's an interesting place to take in some commerce and sights, maybe find some vintage pages of Vogue to decorate your bathroom at home with. The vendors are usually quite friendly and willing to haggle if you are spending. Many of them are selling eiffel tower keychains, but several of them have some unique finds.