The Metro - Paris

Click the above for a clearer picture

Same as London, to backpack you have to know "The Metro" of Paris
The above is a small map of The Metro, Click here for a bigger map
The ticketing system is a big difference dough.. read the below for more information.

Ticketing

Tickets are valid on either the métro, buses, or the central Paris RER trains (zones 1 & 2), as well as certain select venues, such as the funicular at Montmartre. Single tickets (€1.60) may be purchased at the station counters each time, but the better value is a carnet of 10 (adults: €11.40; children ages 4-9: €5.70), which will save you queuing. Ticket books (and certain passes) may also be purchased from a network of 1,500 retailers approved by RATP — including bookstores, newsstands, and tobacconists.

Another option for frequent travel during a short visit is the Mobilis unlimited 1-day pass, available in various denominations according to the zones of travel (not valid to, or from, CDG and Orly airports). The pass may be purchased in advance; its day of validity starts upon the first use, and ends at around 12:45 or 1:00 a.m. the following morning, when métro service ceases.

Parisians themselves rely on either monthly or weekly passes (coupons) which are carried in a gray plastic slipcase with the Carte Orange. They are the most economical tickets to use on the entire RATP network, provided you are in Paris long enough to benefit from them. Although some station ticket agents may balk at selling these to tourists, anyone is permitted to buy them.

The weekly pass (coupon hebdomadaire) is valid for unlimited travel from Monday to Sunday; it may be purchased until Wednesdays for the current week, and starting on Fridays for the following week (no passes are sold on Thursdays). The monthly pass (coupon mensuel) begins on the first day of the month and may be purchased starting on the 20th of the prior month. You'll need a passport photo to place on the pass; be sure to bring extras from home or purchase one for about €4 from machines in the main stations.

There are also special passes offered only to foreign travelers, called Paris Visites, which are valid for either 1, 2, 3 or 5 days' unlimited use on the entire RATP network, and may be purchased online before your departure to France. For métro travel alone — within Paris city limits — these are not as economical as the coupon hebdomadaire, but they can begin on any day of the week (rather than just Monday to Sunday), and provide 20-35% discounts (or 2-for-1 tickets) on Paris boat trips and certain other attractions. Another advantage is that they can be purchased for certain travel zones, either just within Paris, or for trips as far away as Versailles, Disneyland-Paris, or the airports.Fares vary according to number of days and travel zones selected; children 4 to 11 years old are half-price (kids under 4 ride free of charge).

Have fun backpacking in Paris!