Paris is an easy city to navigate by public transportation, with several modes of transportation to choose from. The Metro, its subway, is the fastest way to travel, offering access to most popular tourist spots like the Louvre and the Eiffel Tower. The Reseau Express Regional (RER) offers rail service to the suburbs of Paris, Versailles, Disneyland Paris and the airports. Tour buses allow you to get on and off at various popular sites, and are a great way to see the city.
You'll find tickets and passes for all forms of transportation available at tobacco stands, Metro station ticket windows and vending machines. Paris offers a number of economical options to save on transit fares including a Visit Paris Pass; a Carnet, a pack of 10 tickets on any mass-transit option at a reduced price versus single ticket; and a Mobilis, a one day bus and metro pass, economical if you're visiting many places via mass transit in one day. Maps are free at Metro stations and many hotels.