Transilien Paris-Saint-Lazare is one of the sectors in the Paris Transilien suburban rail network. The trains on this sector depart from Gare Saint-Lazare in central Paris, as well as from Noisy-le-Roi station in the suburbs. Transilien services from Paris – Saint-Lazare are part of the SNCF Saint-Lazare rail network. There are two groups of Transilien lines in the Saint-Lazare sector, marked "J" and "L".
Service consists of the following lines:
The lines signed "J" serve 260,000 passengers per weekday, and the lines signed "L" serve 290,000 passengers per weekday. The two lines are the busiest lines in the Transilien system, excluding lines signed as part of the RER.