I would suggest you have the kids look at the Let's Go guide for Paris - as well as the Thorn Tree section of the Lonely Planet website. I'm sure there are a ton o things there that students would love to do.

The Moulin Rouge ? A burlesque cabaret ?

Of course I'm just kidding. Why not poll them to find out what in generic terms they might like to do, then come back and we can give you specifics about museums or galleries or places and events they may like.

I think a bike ride or a segway tour around Paris would be right up their alley. There are organised tours for both, lasting a couple of hours, if you look them up on the net.

Sometimes they may just like to have the free time to do whatever they want - anything or nothing, and just chill.

I think a segway tour sounds fun, don´t know if they do them at night or when this evening will be (time of year, it does stay light late in summer).

whatever you do, do not take them to Moulin Rouge, they will hate it, that isn´t even funny in case it is perceived as a real possibility. It´s only something older people might like as it is quite old fashioned in concept and tacky.

I dont have any great suggstions for a large group of teen boys, to be honest.

If they are car crazy, they will love the automobile showcases on the Champs Elysées (they are much more than 'showrooms') -- Mercedes, Renault, Peugeot, Citroën, and Toyota, not forgetting BMW on avenue George V two blocks away. Most of these places are a mix of concept cars, the latest models, museum pieces, plus a shop with all of the souvenir and logo items. The Renault place has a free photo device where they can email photos of themselves in super cars to all of their friends.

And of course the Champs Elysées also has the Nike and Adidas superstores as well as the Virgin Megastore on four levels. While most adults are dismayed by the Champs Elysées, teens absolutely love the place and it is one of the principal hangouts of the local youth on the weekend.

I agree the Champs Elysees is a mecca for teens and a very lively place at night, brilliantly lit and a lot of fun to stroll. (I'm an adult and I don't hate it.) FNAC is also there and great for music listening and shopping.

Thanks for all the feedback. I had already thought that the Champs Elysees would be a good place to hang out, because I remember it being swamped with teens when I was there for solo travel in 2010. I hadn't even thought about the auto showcases...they would probably love that, plus just the business of the avenue.

Fat Tire Bike tour, Paris by night, totally fun .

Frankly why aren't kids in charge of doing some research. You should put them in charge, ask for them to come up with three ideas, you make final choice, I do this with my kids, as young as 11 , kids should have some responsiblity for trip planning.

Also a great museum , ( both my teen boys loved) is the Invalids Army museum it does not have evening hours after September but you could /should work it in a daytime schedule, its a great musuem.

Something to see on a Friday night (though not necessarily to take part in) is the roller blade rally:
http://www.pari-roller.com/index.php?p=101

It takes about 10-15 minutes to pass any one spot (the route for each week is announced a day or so beforehand, on the "Parcours" link on the site above).

I think the Champs-Elysées could work. The girls can go shopping in Sephora, Ann Tuil, Zara, even go into Louis Vuitton. The guys can check out Celio, Nike, and if they are bored get a sandwich - or go up the Arc de Triomphe, if you aren't already planning on that.

Otherwise, hanging out on the Champs-Elysées at night can sometimes be fun. It's such a typical thing to do for French and Parisian young people - sit and drink, have a picnic, play football, walk up to Trocadéro.

You could also make some sort of 'picture' photo treasure hunt...this could be funny and entertaining for them.

I also think the Champs Elysees could be a good solution, but as I think back to when I was between the ages of 15 and 17 and on holiday in France, my major preoccupation was meeting french girls between the ages of 15 and 17, closely followed by music.

As a bit of a left-field suggestion, perhaps some of them might like to go to a music venue (such as the Fleche d'Or in the XXe) where they can see a live band and (more importantly) live, french girls in close proximity.

The older ones can have a beer (and sneak out for a crafty cigarette of course) whilst having an experience that I imagine most of their peers won't have have had on any trips they might have made to Paris.

There are of course plenty of other venues which may be closer to wherever you're staying, but as some of the group are practically 'adults', something a little more grown-up might be suitable...

Another vote for letting the guys decide for themselves. It's their trip and they might get something out of being responsible for planning their free evening.

It's nice to have faith in younger generations.

be careful IMO before taking the lads on any Segway or Fat Bike tour, etc as you may be considered to be liable if anything should happen to them on those tours - perhaps - something to think about at least as when something grim happens parents may sue anyone involved - claiming it was poor judgment to have them riding any vehicles on the streets of Paris.

Are they speaking French = perhaps just take them to the Champs-Elysees or other venue where there are cinemas, where it is hard to get injured except perhaps on popcorn?

I believe they have recently raised the legal drinking age in France to 18 to combat binge drinking amongst French youth - I wonder if that law is any more enforced than the previous age limit of 16 for beer/wine now 18 - when my son was growing up in France he bought booze from age 14 at Carrefour without any problem.

Accompanied minors are allowed to drink. It is only unaccompanied ones who will be refused beer or wine under the age of 18 -- but you are right, PalenQ: they are unlikely to check ages if you look like you are at least 15.