Five of us will be having a 12 hour layover in Paris arriving before noon and are trying to figure out the best way to get around. Unless we think of a specific sight, we were considering a cruise with Batobus on the Seine that stops at different landmarks but are concerned with the amount of walking it will require taking the boat since one of us had a recent knee replacement. Would it be easier going on the Hop On Hop Off Bus or getting a ticket that combines both boat and bus? Our only stop maybe the Eiffel Tower but otherwise we would just like to enjoy the city and go for a nice meal. We are not locked with this form of getting around so any ideas would really be helpful.

If you have no intention of getting off at any of the stops, the bus would give you better views. If you want to get off and reduce walking, you would probably need to book a private tour. It would not be cheap. From any boat stop, you would have to walk up slopes/stairs to the street level, then to whatever site you are thinking of going = a lot of walking.

>>> Our only stop maybe the Eiffel Tower but otherwise we would just like to enjoy the city and go for a nice meal.
What is your definition of a nice meal? Are you willing to pay for at the upper end of a Michelin star rated price range?
One interesting way, if you have the budget, that combines Eiffel tower and a "nice meal," would be to book lunch at the Jules Verne restaurant at Eiffel tower if your flight is early enough and if you are visiting Paris after May 31 (which is the earlier day with any lunch opening when I looked at their reservation system.) It would not be cheap, but it offers you: ability to use an express security check gate into the Eiffel tower secure area, ability to use an elevator dedicated to the Jules Verne diners only, and given access to the 2nd level from the restaurant without any additional cost, and allowed to use the elevator dedicated for the diners to get back down. The restaurant is going through a renovation and is scheduled to open late May. They had been a Michelin one-star restaurant under previous incarnations. If you want to visit Eiffel tower and go up independently, you need to secure a timed reservation slot.

Five people without luggage? Or with?

With five if budget is not a huge constraint I would just take a taxi to a specific place and then wander around. Maybe Notre Dame? Maybe the Trocadero. Taxi to the right bank is a 50 euro fixed price. To the left a 55 euro fixed price. From the Trocadero walk down the hill and across the river to the Eiffel Tower. Then maybe take a boat ride (1 hour) and see all the beautiful sights you can see from the river. Head to rue San Dominique to find a restauraunt that you like. Or walk over to rue Cler, the pedestrian market street in the 7th.

You could take the RER back to CDG or you could just repeat with the taxi or an Uber. I hope you get a beautiful day.

By the way, for my money, I'd rather go to the top of the Arch de Triumph than the Eiffel Tower. Or even Tour Montparnasse, but that will put you in a part of town that won't maximize your time.

How recent was the knee replacement?

10 days out from it is one thing,
4 months out from it is another.

The Hop on, Hop off bus offers a good value and overview. However, be aware that your friend with the recent knee replacement might have difficulty with the steep steps up to the top deck. That friend will, however, be able to enjoy the same narrative in the air conditioned downstairs level.

The dock for Vedettes de Paris by the Vert-Galant statue is reached by a very steep, long flight of stairs, then "bouncy" steps leading out to the boat. Not easy with new knees, possibly. The Bateaux Mouches dock is more user- friendly, although we prefer the Vedettes boats.

Belinda, thanks so much for your suggestions! We won't be traveling with luggage which makes getting around a little easier. I think the only problem I foresee is that we are five people and will probably need 2 taxis unless there are large Ubers we can take.

I think with Uber, you can specify larger vans when you book your ride.

That is true about the hopon/off bus and the stairs to the upper level, which is kind of the main reason to do one of those (at least to me, that's the only reason I do thejm, for an excursion and the views on top). However, it ios true it can get you around to major tourist points and would be easier than metro, for sure. It can be a bit slow on the Right Bank in my experience, due to traffic. Not so bad on the Left Bank.

There are several other companies that do boat cruises compared to Vedettes du Pont Neuf, and I think they are all easier to reach. I've never taken one from the Eiffel Tower area though. I have done Bateaux Parisiens (which being at river level, there are some stairs down to it from the quai facing Notre Dame (on the Left Bank side), but there is no bouncy thing and the stairs aren't that long. I also have taken the big one, Bateaux Mouches and that could be the best om that regard, if I remember correctly. Boarding is on the Right Bank near Pont d'Alma I think you just walk to where the boat boards (level, more or less, but those big granite stones) and then there is a "gangplank" onto the boat. it isn't bouncy and if there are steps down to it (which there well could be given it is on the Seine, so you are going down to where those roads are along the Seine), it isn't as narrow and steep as the smaller stairs to one of the smaller companies. They do sell a combo ticket for 20 euro, l'Opentour plus Bateaux Mouches. Personally, all of this seems to much for just a 12 hour break from the airport. I'd just do the cruise maybe and then wander around the Notre Dame area or something. All of the cruises do a loop as far as I know.

I would recommend taking a Uber. Me and 6 other friends (including luggage) were in the same position and we were fine.

There isn't a problem with 6 poeple and luggage from CDG with a regular taxi.

Must be huge taxis - five people sit in rear and on up front? Or do some sit in the trunk?

StCirq is totally correct. I know it's been years since you were in Paris so you may not remember - but there are large taxis . . .