Many customers asked me what type of transport tickets they should buy in Paris. I may as well share it here with all travelers.
To use the public transportation at Paris, you have different options of travel passes and tickets : single-use tickets, daily pass, weekly pass or monthly pass. It all depends on your duration of stay in Paris and your frequency of using the public transportation in a day.

The 巴黎市區單程票 single–use ticket (named ticket T+) is for one ride within zone 1 and 2 ( Paris city) regardless of the distance. You can use it for the metro, bus (except Orlyval for orly airport), RER, funiculaire of Montmartre, Montmartrobus, or night buses.

A single ticket T+ permit changes between metro and RER lines ; or bus to bus ; or bus to tram but not metro to bus or vice-versa. You can change within the metro and RER networks as many times as you wish but once out of the exit, it is finished. Well, it does has a time limit of 90 minutes validation after starting.
The price of one ticket T+ is 1.90 euros and a book of 10 tickets is 16.90 euros. You may buy a rechargeable card from the counter for 2 €. Then you can recharge 10 tickets on it for 14.9€. If you take the public transportation less than 4 times per day, take the Ticket T+.

The « Mobilis ticket » 巴黎一天票 is a single day ticket for unlimited travel. You can use it in different transportations as the T + ticket.

7.90 euros for zone 1-2 (Paris city). With Mobilis card, you can jump into the public transport whenever you want, it is a kind of freedom for unlimited travel.
If you are staying for more than 3 days and use the public transportation often ( use more than 17 tickets T+ ), the weekly pass 巴黎一周票 might be a good option. Note that the weekly pass counts from Monday to Sunday in spite of your starting day.

The weekly pass is 22.80€ and it allows you to travel unlimited in zone 1 to 5 (access to CDG airport, Orly, Disneyland or Versailles).
Remark: weekly travel card is a plastic card which you can recharge . You need to have an identity photo (you must put the photo on your card within one day after starting) The plastic card is 5 euros (valid for ten years).
In most cases, the Paris visite pass is expensive and not worth using.
Tickets can be bought from the machine in the metro stations. You can address to the information counter there too.
Have a nice trip and contact me, celiasoparis if you need guide and travel planning service in Paris.
巴黎樂遙 CeliaSo, Paris. 27/10/2019