Traveling with teens (16, 14) to Paris, Top 5 sights?

Maybe the Catacombs and the Eiffel Tower?

Catacombs for sure, and you won't be able to keep them off the ET. Also can't go wrong with a Seine boat cruise (but skip the dinner). Trocadero at night with the ET lit up. Notre Dame towers. Maybe the Deportation Memorial for a sober moment. Street markets. Watching the traffic ballet at Bastille or Etoile. Try the Velib bikes on quiet streets. And I believe they close streets on Sundays except for rollerblading, find out when and where that is -- you watch, let them blade.

Basically, give them all the climbing and descending and biking and blading they can handle. You go to the museums early while they're still asleep.

what always worked for us was to turn over pleasing teens to the teens -- let them each choose the one or two things they most want to do -- give them a good illustrated guidebook

My top 5 would include
Going up in the Eiffel Tower
River cruise at night
Rodin museum and the Orsay
Notre Dame and explore the Latin Quarter
Something unique is the Sewer Tour
Perhaps, going to Versailles-see the fountains, you can rent a bike or boat
visit Lauderee-bakery for a yummy treat
Shop or visit a market
You could also do a bike tour of the city
I would try to mix it up and add variety so its not just museums and churches. :)

google ....cool stuff in Paris. Lots of fun things to do .Also I recommend a chocolate or bread tour.

My teen boys loved the Invalids Army Museum... and my 11 yr old daughter and I like it too!
A bike tour is super fun for whole family.. I especially enjoyed the one to Monets Gardens.. and I am particularily a fan of Monet or gardens.. but this tour takes you to a market.. where you buy picnic supplies.. then to a river bank where you enjoy the picnic.. then a nice ride along a river... on a decommissioned rail line that has been converted to a bike/pedestrian path ( so not hilly) ... there is only one slight hill to deal with.. and I managed ( and I was over 45 and not fit, lol ) Fat Tire Bike Tours .
Catacombs were a hit with boys but daughter chose not to visit..
Climbing the stairs at Eiffel Tower ( shorter line, plus cool view as you go up)
Climbing up the Towers of Notre Dame( lines here are VERY slow moving.. go BEFORE it opens.. at least 40 minutes ahead of opening. and get in line ( side of church.. not front)
Ice cream breaks every day,

I made all my kids do some research and come up with their own three "must sees" .. I think it really helped them enjoy their visits as they were invested in trip and not just being dragged along . It was in fact my older son who discovered the Catacombs.. I had been to Paris many many times over the years and had never heard of them.. ( this was 10 years ago now) and hadn't been on forums much before that... nowadays its easy to research and find sights .