No 2 - Batobus
Use Batobus (Boat-bus), and cruise between sites on the Seine on this hop on and off service with unlimited journeys.
The panoramic boats are a great way to travel from Notre Dame, to the Louvre or Eiffel tower. I really enjoy the perspective of being on the water, but perhaps it's just my love of boats...
The boats run a circuit with 8 stops at a frequency of aprox every 15 minutes, it takes on average 11 minutes between stops.
Route
North bank:1. Hôtel de Ville2. Louvre3. Champs-Elysées (Place de la Concorde)
South bank:4. Tour Eiffel5. Musée d'Orsay6. Saint-Germain-des-Prés7. Notre-Dame8. Jardin des Plantes
Note that the route is a circuit, crossing the Seine to the opposite bank may save you completing the entire circuit
Tickets
Tickets are available at each kiosk/stop or online!
They are expensive, but offer unlimited journeys, with 2 ticket types available:24 hours or 48 hours (from time of purchase)Worth the experience.
Operating times
These vary through out the year, generarlly from late morning until evening.
See these here: Bato bus times