Paris Metro Map ( Click the map to enlarge it!)
Paris has an excellent underground train system, known as the Métro (short for Chemin de fer metropolitain, Metropolitan Railway). Although you will probably take the RER subway train from the airport to Paris, don't be confused: RER isn't the name for the "French subway train", and only a few large stations serve the RER network of trains. Look for the Metro stations, marked with a large "M" sign.
There are 16 Metro lines (lignes) (1-14, 3bis, and 7bis) on which trains travel all day at intervals of a few minutes between 5AM and 12:30AM (Saturday night/Sunday morning: 1:30AM), stopping at all stations on the line. Times for trains can be seen on an electronic scrollboard above the platform. Line 14, which is fully automated, is called the Méteor. Scheduled times for first and last trains are posted in each station on the centre sign. Generally, except for early and late hours, travellers should not worry about specific Metro train times; just get to your station and take the next train, which will likely be in 5-10 min.
Visitors traveling to or from the Airport/train stations with heavy luggage need to keep in mind that changing metro lines might be difficult at times, especially at major metro intersections. Moving from one platform to another generally involves walking up and down multiple flights of stairs and elevators are few and far between. It might be a good idea to check out the Bus routes and timings and see if one can find a convenient bus connection.
Many of the trains do not carry destination binders. All lines on the Paris metro run end-to-end with some trains terminating at certain stations. This practice is common only in peak hours and if you are on a metro train that terminates before the last station, the driver will make an announcement (in French). Listen carefully for signs that the train is terminating before the end of the line.
The lines are named according to the names of their terminal stations ( the end of the line). If you ask the locals about directions, they will answer something like : take line number n toward "end station 1", change at "station", take the line nn toward "end station 2" etc. The lines are also colour-coded.