Batobus Paris - Navettes fluviales sur la Seine. I love this service. It has seven stops-- and you can ride for a while, then get off at a stop that interests you and explore the neighborhood. When you are through, go back to the landing you got off at and just wait for the next Batobus to come around. Then continue on to some other stop you want to explore. The views are tremendous and it's a great way to get acquainted quickly with Paris.