Seine River Cruises - advance tickets needed?

For an evening cruise we took this one: www.vedettesdupontneuf.com, No dinner just the cruise - we enjoyed it. I believe the website contains a coupon which they will honor. No reservation necessary - just show up a few minutes early or call from your hotel.

It didn't sound like you were planning on doing a dinner cruise, but if you are I would recommend against it. They are overpriced and the food isn't very good from what I understand. I would just have a nice dinner nearby and then do the cruise afterwards. I didn't mention the Batobus as a substitute for the narrated cruise. It is just a nice way to get around. The metro is great, but underground and not very scenic! :-)

While not totally necessary, it will offer you peace of mind if you buy them ahead of time.

I wouldn't bother to buy them ahead of time on the internet. What if something happens and you end up not being able to go? If it makes you feel better, buy the tickets earlier in the day. I don't know if you are aware of the Batobus, but it is a boat-bus that goes up and down the river. There are multiple stops on both sides at the major tourist stops (Eiffel Tower, Notre Dame, Louvre, etc.) and there is minimal waiting. The boats probably come every 15 minutes or so. It is a fun way to get around. I don't know how long you will be in Paris, but a multi-day pass is only a couple of euro more than a one day pass. Their route is essentially the same as for the cruises you are wanting to do, but there is no narration.

Peace of mind would be good but then....I also appreciate Andrea's suggestions.

We aren't planning on a dinner cruise based on many comments. I like the idea of taking the scenic route to get around. A point well made, Andrea!