I think the best thing that my mom and I did to prepare for our trip was to buy both the Paris Visite pass for the Metro, and the Carte Musées pass for the museums. Although slightly more expensive if you buy them in the U.S. first, it took some of the pressure off of having to find a location that sold the pass. You purchase the passes depending on how many days you plan on using them. They both come in one-, three- and five-day options.
The museum pass allows you to enter most of the major museums and monuments without waiting in line for tickets (note, the pass doesn’t work for entry into the Eiffel Tower). Prices range from 12 € to 36 €, it saved us a lot of time and hassle. Plus, we got to use our euros for other purposes, like taxis and such. The only things that our pass didn’t work for were the Eiffel Tower, and the gardens at Versailles. We were able to get into the palace with the pass, but not the gardens. Also, we couldn’t get into the special da Vinci exhibit in the Louvre, but it worked in the Louvre itself.
The metro pass (valid on the metro, the RER trains and the buses) paid for itself in our situation on the day we arrived in Paris. We had taken the TGV (trains grande vitasse – high-speed train) from Nice to Paris. We arrived at the Gare de Lyon to be greeted by a huge demonstration outside the station. The demonstration blocked all taxis from picking up passengers. With no other way to get to our hotel, we had to tackle the Paris Metro system first thing. Thank goodness for our passes, because the ticket lines were incredibly long. We learned a helpful tidbit of information. When you insert the ticket (which is about the size of a ph strip and is kept in a sleeve to maintain it magnetic strip), you have to take the ticket out again before the turnstile will let you through. We learned it the hard way when my mom made the mistake, and then tried to put the ticket through again and it wouldn’t let her through. Thank goodness for a very nice French woman who put her ticket through and then held the doors for her saying “Come on mama, come on mama.” The Metro pass is also sold in day parts, but also by what zone or region you want to be able to travel to. If you want to see Versailles, or Euro Disney, those are in the furthest zones. We bought a five-day pass in the farthest zones, and I believe it cost each of us around $60.
Just as a Metro side-note, if you want to know which train to get on, you’ll have to determine which direction you’re heading. Note the final destination on the line in the direction which you are heading. That is how the trains are marked.