For occasional visits in Paris & the suburbs buy a "Ticket T+" each time (1,90 EUR) or a book of 10 tickets (14,50 EUR adults, 7,25 EUR children from 4–10, under 4 years old the children travel free). This ticket can be bought at the station and in the "tabac" (cigarette shops). The "Ticket T+" is usable for 1h30 with unlimited trips between metros only OR bus & tramways only. You can’t do metro & bus. The tickets have to be validated each time you get on.
For most of the stays buying a pass is the cheapest way. It is valid in the zones indicated for bus, metro & tramway, RER (regional railway) and also the cable car in Montmartre. They can be bought in the metro stations.
For a 4 to 7–day stay the most economical is the "Navigo Semaine". For zones 1 to 5 it is 22,15 EUR for the week. Note: It is valid from Monday morning to Sunday evening and you will need to buy a "Passe Navigo Découverte" for 5 euros. This pass is for life & is rechargeable but you must provide a identity photo or a copy (3cm tall x 2.5cm wide).
For a stay less than 3 days or for a stay straddling the 2 weeks it is better to buy a daily "Mobilis" for zones 1 & 2 for 7,30 EUR (no picture required).
2) Children from 4-11: Choose "Paris Visite" zone "Paris Centre" at 5,80 EUR for 1 day, 9,45 EUR for 2 days, 12,90 EUR for 3 days & 16,60 EUR for 5 days (no photo needed).
Note: There is a ticket specially created for young people under 26 called "Ticket Jeunes week-end". It is valid only for Saturdays, Sundays & Bank holidays and costs 4 EUR zones 1-3, 8,70 EUR zones 1-5 (no photo needed).
Airports: This is more complicated… Roissy is in zone 5 and Orly is zone 4. For Roissy I would advise you to take the RER at 10,00 EUR (7,00 EUR for children, this is a train which serves Paris & the suburbs). At Orly there is the "Orlybus" which is 9,90 EUR.
Buying a pass should be cheaper. Up to you to decide the best option. Look closely as your pass can also cover Versailles (zone 4) & Disney (zone 5).
For your information:
- "Mobilis" is 12 EUR zones 1-4 & 17,30 EUR for zones 1-5
- "Paris Visite" for Kids zone "Paris + suburb + airports" at 12,25 EUR for 1 day, 18,60 EUR for 2 days, 26,10 EUR for 3 days & 31,95 EUR for 5 days.
For more info: www.ratp.fr