Metro stations are the easiest place to buy tickets; you’ll find automated ticket machines and walk up windows. I would recommend using the walk up windows during busy periods. The automated machines can be a bit confusing and it is aggravating to have a group of people line up as you fumble with your ticket purchase.

You may even be tempted to buy tickets from someone standing next to the machine. Avoid these frauds, they’ll sell you used tickets at a premium.

You can purchase single tickets or a pack of 10 (carnet). A ticket will allow you to transfer between multiple metro trains, However it doesn’t allow unlimited transfers of buses. You’ll save money and time buying tickets 10 at a time. These are good options for those visiting Paris for less than a week.

You can purchase weekly tickets that are valid Monday through Sunday. these are not available to purchase every day. if you buy one on Friday-Sunday, they won’t take effect until the following Monday. These unlimited tickets come in several flavors, Carte Orange and Passe Navigo are the most common. Short term visitors may want to look into the Paris Visite pass, which ends up being cheaper than individual tickets, more expensive than Carte Orange or Navigo, but you pay for just one to 5 days.

Unlimited travel saves money and time

you’ll want to upgrade to a carte orange or navigo pass if you will be staying longer or returning at a later time. Carte orange is an older method for purchasing a ticket that allows you to pay once a week or month. The ticket allows unlimited use of the metros or buses within the designated zones. You will probably want the basic set, zones 1 and 2, this includes the city limits and the suburbs right outside the city.

You will need to provide a passport style image; most major metro stops feature photo booths for this purpose. Just take the photo to a ticket booth and request a carte orange for the desired time period. They will create an identity card and hand you a holder and special ticket. You’ll need to sign your id card and write your id card number on your ticket to make it valid.

To use the metro, pass your carte orange ticket through the collectors as you would a normal ticket. On buses, show the driver your valid ticket and id when you get on.

Carte Orange is being phased out in favor of Navigo.  It may not be available for much longer.

Navigo

Navigo is much more convenient to use. However, you need to mail your passport photo to the RATP and receive your identity card in the mail a few weeks later. It uses RFID technology instead of a ticket for passing through the toll gates and getting on a bus.

You can also register your Navigo pass to work with the Velib rental bikes. There are two types of Navigo passes, depending on whether you live/work in the Paris vicinity or not.