Île-de-France Mobilités, the regional transport authority for Paris and its suburbs, is committing €3.8 billion in 2026 to a wholesale renovation of the RER and metro networks, the largest annual capital programme in its history. The agency confirmed the figure on Friday alongside an updated timetable of weekend closures and bus-replacement services that will run through to the end of the year.
The bulk of the spending is concentrated on the RER B, which carries roughly 1 million passengers a day between Charles-de-Gaulle airport and the southern suburbs and which will receive its first MI20 trains in December. Engineering on the line has already required the closure of Gare de Lyon between April 30 and May 3, and the agency has flagged a longer shutdown over Ascension weekend.
Line 13 of the metro, the most overcrowded on the network, will close from start of service on alternating Sundays through October to allow signalling work in the Brochant-Asnières-Gennevilliers section. A revised concentric service pattern, in which trains will turn back at Saint-Lazare, will operate during the closures.
Smaller envelopes within the package include €240 million for the Tramway T9 extension to Orly, €310 million to convert the existing line 14 platforms to accept eight-car trains, and €175 million in catch-up renewals on the suburban Transilien lines, where rolling-stock reliability has been the most frequent passenger complaint in successive customer surveys.
The capital plan is paid for through a mix of the Île-de-France region, the City of Paris, the Société du Grand Paris levy on commercial property, and a €1.1 billion bond issued through Caisse des Dépôts in March. Industrial-action risk remains a worry: SNCF and RATP unions have given notice of a series of stoppages in May and June over working conditions linked to the modernisation.
Île-de-France president Valérie Pécresse said the agency was "spending now to give Parisians a network that has been promised for fifteen years". The most visible deliverables — the MI20 fleet on the RER B and the autonomous Grand Paris Express line 18 to Versailles-Chantiers — are scheduled to be in passenger service by the end of 2026.