Métro
The Paris Métro consists of 14 lines distributed throughout “Petit Paris” and primarily operates within the core city area (within Zone 2). Each Métro station entrance is equipped with ticket validation and Navigo card readers. Simply insert your ticket into the validation machine and retrieve it to enter the station. The Paris Métro has a long history, so many stations do not have elevators or even escalators. While efforts have been made in recent years to address this issue, stations with elevators or escalators are still relatively few. Therefore, if you have a lot of luggage or heavy items, taking the Métro may be inconvenient. (Operating hours: 5:20 AM to 1:20 AM; extended to 2:15 AM on Fridays, Saturdays, and the eves of holidays)
RER
The RER (Réseau Express Régional) is a regional train network serving Paris and its suburbs, operating within the Île-de-France region. It differs from trains like the TGV and TER, which operate between cities. The RER is partially managed by the RATP (Régie Autonome des Transports Parisiens) and partially by the SNCF (Société Nationale des Chemins de fer Français). Currently, there are 5 RER lines: A, B, C, D, and E, connecting “Grand Paris” and “Petit Paris” and spanning across Zones 1-5. If you want to visit attractions outside “Petit Paris,” such as the Palace of Versailles or Disneyland Paris, you’ll need to take the RER. (Operating hours: approximately 5:30 AM to 1:20 AM daily)