Works in the southern sector of Île-de-France: disruptions and alternative routes

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On this page, find the details by period of disruptions related to the works on the RER B and C lines (south and south-west of Paris), as well as the alternative routes to choose to get around.

Île-de-France has been divided into 5 sectors (South, East, Centre, North-East and North-West) to better understand the impact of disruptions on the public transport network on a regional scale. During the different periods, alternative routes may save time compared to the usual alternative route.

To simplify your travels

One month before the start of the work, the Île-de-France Mobilités route planner (available on our website and smartphone application) will take into account closures and disruptions and will allow you to anticipate your journeys.

Closure for works and alternative routes: the recap by period

Work information from 17 to 22 August 2026

1. Reminder of closures

From 17 to 22 August 2026, the RER C is closed between Gare d'Austerlitz and Pontoise, Saint-Quentin-en-Yvelines and Versailles-Château.

2. Alternative routes to take during the period

From 17 to 22 August 2026, the RER C is closed between Gare d'Austerlitz and Pontoise, Saint-Quentin-en-Yvelines and Versailles-Château.

Take alternative routes to reach Paris.

To get to Paris from Saint-Quentin-en-Yvelines, Saint-Cyr, Versailles-Chantiers, Vélizy, and Viroflay Left Bank:

  • Take the U line to Versailles-Chantiers then the U line to La Défense
  • Or take the N line to Versailles-Chantiers and then the N line to Gare Montparnasse

To get to Paris from Versailles

  • Take the L line at Versailles - Rive Droite towards Gare Saint-Lazare

To get to Paris from Meudon Val-Fleury

  • Take the N line at Meudon towards Gare Montparnasse

To get to Paris from Issy

  • Take metro 12 to Mairie d'Issy towards Paris
  • Or take the T2 tram at Jacques-Henri Lartigue towards Paris

To reach the Palace of Versailles from Paris

  • Take line N at Gare Montparnasse to Versailles-Chantiers
  • Or take the L line at Gare Saint-Lazare to Versailles - Château