The framework of the Paris subway system is the 14 metro lines crisscrossing the entire city, complemented by the ever-expanding (RER) suburb-bound Express lines. Metro lines used to be known only by the names of the final stop at each end.
One example is Nation – Porte Dauphine (Line 2). It works like this:
If you enter a Metro station somewhere in the middle of this line and your destination is a stop in the direction of Porte Dauphine, look for signs naming the final stop of the line in that direction (Porte Dauphine). Idem in the other direction. Those signs will lead you to the correct platform for your train.
If your destination is not on your current line, your trip will require a change of lines. On the Paris subway system, you want to identify the line your stop is located on, as well as the final stops at each end of that line (you know, the ones that give you the name of the line).
Then, you want to find a station where your current line and the line of your final destination cross; you will change lines there. That line transfer is called “correspondance”. You’ll see orange correspondance signs inside the stations where these transfers are made (not all stations have correspondances).
A correspondance amounts to walking (changing) over to the desired line(s). Once your correspondance completed, you’ll be on the correct platform and in the right direction.
Once again, the key to not getting lost in the Paris subway system is to note the end stations (i.e., the name of the line) within which the station where you’re headed is located. As you walk the halls towards your target line(s), approaching platforms, a blue sign on the wall will display the end of line name, as well as your stop among all the stops remaining in that direction.
The names of the stations are displayed inside the train cars and on station walls. Simply watch for yours.
Note: A correspondance may be just a quick hop to the next platform, while the longest ones, like Metro Châtelet, could (although rarely) involve up to a 3 or 4 minute walk, sometimes up and down steep stairs, with some older stations having no escalators. Guess why Parisians stay so slim…
For better clarity, lines have been given numbers and color codes in the Paris subway system and all things Metro . This will help you recognize your targeted lines more easily.
The lobby of each Metro station usually has a Paris Metro map electronic itinerary with all stations listed. On it, you locate your Metro stop and you push the matching button. Your chosen stop and itinerary will light up in a dotted string of all the stations within your trip, including line change(s).
A multiple correspondance itinerary can get hairy. Having lived in Paris a long time, I just quickly memorize my transfers. But if you have to, there’s nothing wrong with writing the details on a piece of paper or putting check marks on your Paris Metro map.
Some travelers do carry a small Paris guide that includes a Paris Metro map and other useful info. I think that’s smart! A good pocket guide like "Paris Pratique" will actually enrich your Paris experience.
Official Paris Metro map foldouts are freely handed out at any metro station upon request. In French, just ask for a “plan du métro”.
Another option is to look up your itinerary online prior to going out. The Paris transit authority (RATP) has a fancy webpage that gives you detailed routes for linking any two points in the Paris region. The itinerary includes the Metro, RER, city buses and even neighborhood maps for the short walk to your destination. Go to RATP.fr for details.