Especially around the morning and evening rush hour, sometimes the metros are so packed that it’s just not possible to fit inside – in that case, you either must wait for the next metro and hope that there is room or figure out a different way home (a bus or you walk to a different metro station). Most of the time, however, it’s not too crowded. During the early afternoon, when most people are at work, as well as late at night, the metros can be almost empty!
French people (and Europeans generally, from what I understand) certainly like trains a lot more than Americans do, especially in urban areas. Even for longer trips, for nearly anywhere in France, taking a train is often the best option in terms of both time and cost. Although trains (even the high-speed ones) aren’t as fast as airplanes, the boarding process is much less complicated – you go to the train station, find the right track, scan your ticket and get on. No need to wait in a long security line at an airport. I’d say therefore in general, there’s less of a culture of being completely dependent on owning a car. I certainly wouldn’t bother to own one if I lived in Paris permanently.
All the trains in France are managed by the state. The Parisian metro is managed by the RATP (Régie autonome des transports Parisiens – autonomous Parisian transport company) which is owned by the state, as is the SNCF (Société nationale des chemins de fer – national railroad company) which manages all the intercity and bullet trains.
