We will be in Paris for 14 days this summer. Weekday mornings we are taking a French class (zone 2) and in the afternoon plan to visit sights and museums. Our apartment is near the Montparnasse tower. Because we are staying longer than many tourist we are having difficulty deciding what passes (if any) are ideal. Any thoughts?
The Navigo pass will be good for you. It costs about €6 to get a card - you'll need a 1 x 1.25 inch photo for it. Then you can add a one-week pass. The pass goes from Monday to Sunday, so if you arrive on Saturday or Sunday, it won't begin until Monday. Near the end of the first week, you can add another week. Even if you only use it for 4-5 days, you'll at least break even and it's worth it for the convenience. It's good on the metro and the buses for zones 1-6.
The Paris Museum Pass is the only one you should consider. The 6-day pass could serve you well if you plan it out. One of the great benefits is that you can pop in to a sight without debating whether it's going to be worth the entrance fee, and you can leave a sight after seeing only part of it without feeling you've wasted your money. The only sight I can think of offhand that saves waiting in line is the Orsay. At the Louvre you can avoid the line by using the Carousel entrance (the long line is for security, not tickets). At Sainte Chapelle you can't skip the security line, and the Notre Dame tower you can't skip the line. Other sights have short lines or no lines. If you have the energy, you can sightseeing all afternoon and evening. Also group your sights by location. There are sights on the pass that are open once or twice a week in the evening and some that are open every night, like the Arc de Triomphe. Plan to see sights not on the pass either before or after the 6 days of the pass.
Chani's plan is exactly what I would have suggested. The Paris Museum Pass (NOT the overpriced Paris Pass) is a great buy if you use it enough, and the rare tourist pass which allows you to return to the monuments/museums as many times as you wish to. We did the Louvre 3 times on that one - very nice because it's an enormous thing that's impossible to cover in single visit - and you could, say, do the Arc de Triomphe once during the day and again some evening to see the city lights. We bought the 6-day pass for our week in Paris and absolutely got the good of it.
Line up a list of free attractions or those not covered by the pass for your 2nd week: neighborhood walks, churches, parks, cemeteries, markets, the Eiffel from the Trocadero some evening, permanent collection at Petite Palais Musée des Beaux Arts... You won't be bored!
The Pompidou now has a security line outside, and it was very long. (Tickets are still purchased inside.) Museum pass holders had a very short security line to the left of the big line. My sister in law turned to me and said, "that just paid for the pass."
Chani's advice is great.
the major museums have separate security lines for those with tickets or museum passes i.e the Louvre, d'Orsay, Pompidou, Orangerie etc.
You are probably not taking your class in zone 2 but in arrondissement 2 (or maybe it is outside of Paris?) All of Paris is zone 1. 2-5 are further out in the region Ile de France. The zone numbers have nothing to do with the 20 Paris arrondissements all of which are in zone 1. The Navigo Decouverte will take you anywhere in the 5 zones and is as you have been advised absolutely the way to go.
Two weeks is a great first visit to Paris and there are literally dozens of great day trips you may want to try. Chartres, Giverny and Auvers su Oise are probably the most obvious, but there are lots of others. Here are a few we have done recently:
https://janettravels.wordpress.com/category/day-trips-from-paris/
Have a fabulous time.