But Paris also offers a second subway system, the RER, an extended network that connects the entire region with the capital. The trains stop at fewer stations, travel at higher speed, interconnect with the métro grid and are fully integrated with the public transportation system. The RER is linked to both the urban underground and the national train network.

To determine the best itinerary between two points you need to look a map of the métro as well as a map of the RER. But if you have problems figuring out where is what, you can enter the point of origin and the desired destination in the Subway Navigator and let it point you in the right direction. It will indicate the subway lines you should take, list the stations on the way, estimate the duration of the trip and point out where you should connect from one line to another. The route can also be displayed graphically by the Subway Navigator.

The métro does not run 24 hours a day. The first train leaves the head station each morning at 5:30 am, and the last train leaves the head station at 12:30 am. Though the subway is generally a safe mode of transportation, there are nonetheless sections of Paris, as is the case for most metropolis, that it might be better to avoid late at night if traveling in the subway. Well aware of this condition, the RATP has recently introduced the Noctambus, a new night bus system serving Paris and the suburbs. For specific information regarding routes and schedule, the traveler can call 08 36 68 77 14. Note that a telephone charge applies for every inquiry.

Tickets for buses and the subway are almost 50% cheaper if purchased in advance in a book of 10 (un carnet de tickets), costing approximately US$8. The same tickets can also be used on the bus.

Day passes can also be purchased, and offer unlimited travel within a single day on the subway and bus. Other discounts are available to tourists, such as the Paris Visite which buys 1, 2, 3 or 5 dayís unlimited travel on the Paris public transportation system (including the suburban train network), at reasonable rates and in first class. The Paris Visite also offers free or discounted access to a number of sights and attractions.

Please refer to the section on discounts and passes or visit the web site of the Paris Public Transportation Authority, RATP.

In the Eastern region of Paris a new public transportation system is being tested. The TVR, or tramway of the future as the authorities like to refer to it, is a cross between a bus and a rail car. As a tramway, it is mounted on wheels with tires, guided by a rail system and powered by electricity. At the end of the track, it continues its run, turning into a diesel powered bus.