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 15 July to 24 July 2026

1. Reminder of closures

From 15 to 24 July 2026, the RER C is closed from the Gare d'Austerlitz in Pontoise, to Saint-Quentin-en-Yvelines, to Versailles-Château.

From 15 to 24 July 2026, sections of the RER C are closed between Gare d'Austerlitz and Pontoise, Saint-Quentin-en-Yvelines and Versalles-Château.

2. Alternative routes to take during the period

From July 15 to 24, 2026, station closures will take place on the RER C. Prefer alternative routes to reach Paris: - Take line L at Versailles Rive Droite station instead of Versailles-Château station - Between Saint-Quentin-en-Yvelines and Versailles-Chantiers, take line U or line N - To reach the Palace of Versailles from Paris, take line N to Versailles-Chantiers or line L to Versailles-Château - Take line N gare de Meudon instead of gare de Meudon-Val Fleury to get to Paris

From August 17 to 22, 2026, closures will take place on the RER C

Prefer alternative routes to reach Paris:

Between Saint-Quentin-en-Yvelines and Versailles-Chantiers

  • Take the U line to Versailles-Chantiers > the U line to La Défense
  • Take the N line to Versailles-Chantiers > the N line to Montparnasse

To reach the Palace of Versailles from Paris

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

To get to Paris from Meudon

  • Take the N line at Meudon

To get to Paris from Versailles

  • Take the L line at Versailles Rive Droite

Work information from 25 July to 6 August 2026

1. Reminder of closures

From July 25 to August 6, 2026:

  • The RER B is closed from Gare du Nord to Bourg-la-Reine.
  • The sections of the RER C are closed between Gare d'Austerlitz and Pontoise, Saint-Quentin-en-Yvelines and Versalles-Château.

2. Alternative routes to take during the period

From 25 July to 6 August 2026, closures will take place on the RER B and C

Prefer alternative routes to reach Paris:

Between Saint-Rémy-lès-Chevreuse and Massy-Palaiseau

  • Take line B to Massy-Palaiseau > line V to Versailles-Chantiers > line N to Montparnasse
  • Take line B to Massy-Palaiseau > RER C to Pont de Rungis > metro 14 to Paris
  • Take line B to Massy-Palaiseau > line V to Versailles-Chantiers > line U to La Défense

Between Massy-Verrières and Antony

  • Take line B to Antony > OrlyVal line to Orly Airport > metro 14 to Paris
  • Take line C to Pont de Rungis > metro 14 to Paris

Between Robinson/Bourg-la-Reine and Gentilly

  • Take the RER B relay buses which will serve (direct or semi-direct) Bourg-la-Reine <> Porte d'Orléans or the regular buses to metros 4, 13 and 14

Between Antony and Parc de Sceaux

  • Take line B to La Croix de Berny > A Tvm bus to Chevilly Larue > metro 14 to Paris
  • Take line B to Antony > Orlyval line to Orly Airport > metro 14 to Paris
  • Take the RER B relay buses which will serve (direct or semi-direct) Bourg-la-Reine <> Porte d'Orléans

Work information from 7 to 16 August 2026

1. Reminder of closures

From August 7 to August 16, 2026:
- The RER B is closed at Gare du Nord and Croix de Berny/Robinson.

- The sections of the RER C are closed between Gare d'Austerlitz and Pontoise, Saint-Quentin-en-Yvelines and Versalles-Château.

2. Alternative routes to take during the period

From 7 to 16 August 2026, closures will take place on the RER B and C

Prefer alternative routes to reach Paris:

Between Saint-Rémy-lès-Chevreuse and Massy-Palaiseau

  • Take line B to Massy-Palaiseau > line V to Versailles-Chantiers > line N to Montparnasse
  • Take line B to Massy-Palaiseau > RER C to Pont de Rungis > metro 14 to Paris
  • Take line B to Massy-Palaiseau > line V to Versailles-Chantiers > line U to La Défense

Between Massy-Verrières and Antony

  • Take line B to Antony > OrlyVal line to Orly Airport > metro 14 to Paris
  • Take line C to Pont de Rungis > metro 14 to Paris

Between Robinson/Bourg-la-Reine and Gentilly

  • Take the RER B relay buses which will serve (direct or semi-direct) Bourg-la-Reine <> Porte d'Orléans or the regular buses to metros 4, 13 and 14

Between Antony and Parc de Sceaux

  • Take line B to La Croix de Berny > A Tvm bus to Chevilly Larue > metro 14 to Paris
  • Take line B to Antony > Orlyval line to Orly Airport > metro 14 to Paris
  • Take the RER B relay buses which will serve (direct or semi-direct) Bourg-la-Reine <> Porte d'Orléans

Work information from 17 to 22 August 2026

1. Reminder of closures

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

2. Alternative routes to take during the period

From August 17 to 22, 2026, station closures will take place on the RER C

Prefer alternative routes to reach Paris:

Between Saint-Quentin-en-Yvelines and Versailles-Chantiers

  • Take the U line to Versailles-Chantiers > the U line to La Défense
  • Take the N line to Versailles-Chantiers > the N line to Montparnasse

To reach the Palace of Versailles from Paris

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

To get to Paris from Meudon

  • Take the N line at Meudon

To get to Paris from Versailles

  • Take the L line at Versailles Rive Droite