Fodors recommendations.

http://www.fodors.com/world/europe/france/paris/travel-tip_2393288.html

Fodors 4 day highlights. http://www.fodors.com/world/europe/itineraries/best-of-france-57/paris-1/

There are a number of threads that cover this type of question. Do they have three full days or is part of the three days travel in and out? Where are they staying and what are their interests?

If there were three full days, I would visit Ste Chapelle, climb the towers at Notre Dame, stroll Ile St Louis, visit LOrangerie, Musee D'Orsay and Musee Rodin. I would also visit Sacre Coeur and the Eiffel Tower/Trocadero area. If there is more time, I would hit Promenade Plantee and St Denis.

I don't love the Louvre, so it isn't on my list...but do visit if you are interested. It's not my kind of art and overwhelming. I also don't climb the ET....just not my thing.

I'm with denisea but I'd add a quick tour to get a perspective. Probably best on bike or segway. Try FatTires.

denisea has some good suggestions. My only change would be to not visit Sacre Coeur on this trip and visit the Luxenbourg gardens instead. A evening cruise on the Seine would be very nice. We like the Vedettes du Pont Neuf. If you find their site on the internet, you can get a 10% off certificate.

Three days is a very short time for Paris. Be sure you save time to sit in sidewalk cafes and watch Paris go by.

It's a tricky question because there's no "best" things to see in Paris. Everyone has different interests and tastes.

For me an ideal 3 days would include, amoung other things, a visit to the Louvre (which I prefer to the Orsay), the Pompidou Centre, and a performance by the Paris Opera Ballet.

Even for folks who aren't particularly interested in ballet, a performance can be worth it simply to experience the gorgeous Palais Garnier as an audience member- although they do performances at the Bastille as well, so if the venue is important to you, you have to be careful and check before buying tickets.

The Musee l'Orangerie is great because it's small, and it encompasses a relatively broad collection from Impressionist Monet to Expressionist Soutine.

Notre Dame, Saint Chappelle, and the Isle de Saint Louis near each other and popular "must sees" for first time visitors, for good reason.

I would also plan a walk through either the Latin Quarter or the Marais.

But it really depends on their own interests- art, and which period of art, or military history, or medieval history, or shopping, or churches, or ????

I would get a day, at LEAST, with Michael Osman--and maybe two. It would be the BEST way to see Paris,AND really involve the young people. Michael is a wonderful teacher, story teller, in addition to tour guide. You cannot go wrong.