(Please note that fares may increase. These were updated in 2013. Check the RATP website for the most up-to-date fare information.)
For passes, you will just need zone 1 and 2 tickets if you are staying in Paris.
For Paris transit, visitors who are non-residents can buy weekly Navigo Découverte passes, which presently costs €19,80, plus a one-time fee of €5; for the cost of the pass, which is reusable for future visits.
You must bring a photo. There are photo machines in some of the métro stations, but I strongly urge guests to bring a stamp-sized photo from home where you’re less-stressed, since the machines require correct change, may be confusing, and sometimes don’t work. (If you press the wrong button, you might get a 10-inch close up of your nostrils.) It doesn’t need to be passport-quality, so any snapshot will do.
Carnets of Tickets and The New Ticket t+
Carnets of 10 tickets, as always, are also available at métro stations for €13,30; and in Tabacs. Bravo to the new Ticket t+ that allows you 1½ hours to transfer between buses, trams, or métros…although not between the bus and métro systems for some reason. Tickets sold onboard buses can’t be used for transfers, which are marked sans correspondance.
Individual tickets are available as well for €1,70, but the carnet is a better deal and any unused tickets can be saved for your next trip. Or given to a friendly American fellow who lives there.
Where To Buy
Weekly Navigo cards are available at SNCF train stations and métro stations manned by cashiers, as well as métro stations with an actual RATP office.
(Most of the regular métro stations have gone to electronic machines which take cash and some credit cards if they have a puce, or microchip, which replaced human cashiers. Larger métro stations, for the most part, still have cashiers to buy tickets and Navigo Découverte cards.)
What About a Paris Visite Card?
You can also buy a Paris Visite card which costs substantially more but can start or begin on any day. They’re available in 1 (8.5€), 2 (14€), 3 (19€), and 5 (27.5€) denominations. The Paris Visite card offers discounts on various monuments, museums, and other attractions, plus 25% off the Bateaux Parisiens boat, so they’re not necessarily a bad deal. You can buy them online, in advance from a third-party, or during your stay.
(All prices listed are subject to change.)
UPDATE: You can find more information at my post: Paris Transit Options.
More Paris Travel Links and Tips
Official Navigo website
Transilien French Train Information (in English)
Which Paris airport transfers to use
Some of my favorite Paris Travel and Dining Guides
Navigo to Carte Orange details on the RATP site. (The site is in French, although some information is available in English by clicking on the British flag.)
List and links for Paris Cooking Classes
Confused about how much to tip in France?
10 Insanely Delicious Things You Shouldn’t Miss in Paris, according to me
More of my Paris Travel Tips