just returned from Paris. Bought a 5-day batobus ticket. if you have a week-long metro pass such as navigo, the price is discounted. you can buy a 1 or 2 day ticket at the tourist info counter in gare du nord, or longer passes at batobus locations itself.

this is a hop-on hop-off type boat without much narration, although the staff is helpful. the problem is getting to the boat. few metro stops take you there. also, the boat is slow at 90 min round trip. also, once you do it once or twice you really get it so not much need for multiple days.

on the other hand, there are few metro connections that cross the river. if you want to go from the eifel tower to the louve, for example, the boat is the best way.

also, in the off season, the boat runs only 10am to 7pm, which is a bit limited.