During the week, the paris Métro (www.ratp.fr), the generally smooth, efficient subway system, shuts down from one to 5:30 a.m. But on Saturday nights, service is extended to 2:15 a.m. on all 16 lines. the same schedule has been promised for Friday nights and is to be implemented sometime this year. says Marie-Christine Boully-demange of the city's tourist office: "there's a demand for later hours. the city has to talk to the unions, but maybe in a few years, we can have a little more - we hope."

When subways and regular buses take a rest, special night buses pick up the slack in order to keep public transportation rolling 24 hours a day. the Noctilien bus network - which services two circular routes and 40 spokes in all directions - operates from 12:30 to 5:30 a.m., seven days a week. the night buses connect with the city's suburban and long-distance train stations (www.noctilien.fr).

Taxis can be hard to find at night, especially around two a.m., when most bars close. there are stations where drivers are supposed to queue so would-be passengers can find them, but at odd hours you're better off phoning a taxi service. in general, your smartest move for gathering public-transportation information is to ask advice from someone who lives or works in the area. All parisians know which bus lines stop in their neighborhoods, and every parisian has a favorite cab company's phone number at hand.

Finally, as part of a new go-green traffic-cutting program that was unveiled in July, thousands of bicycles are now available for low-cost rental at hundreds of special sidewalk locations around the city (www.velib.paris.fr). Computerized stations will take your credit card to cover the small rental fee, give the bike a high-tech look-over when you return it, and add a steep charge if you've mangled the thing.