Seventy per cent of the national-owned SNCF passenger traffic comes from Ile-de-France, which is expected to bring major disruption to the RER B line particularly.

"It will cut everywhere," said Laurent Souvigné, director of the RER B line, about services across the city, according to Le Monde.

Major civil engineering works is to take place throughout 2023 on bridges, tunnels and tracks that can take lines out for entire days; while interruptions are to be expected on the replacement of tracks, sleepers and ballast, mostly affecting evenings and weekends.

Stations are to receive accessibility improvements, with an eye on the Paralympics and catering to disabled people.

A new Grand Paris line and a new station on the RER E line are to be constructed, while more stations are to be linked to the Grand Paris lines.

The Grand Paris Express is to be created, which will consist of four lines, 68 stations and 200 kilometres of track.

The Charles de Gaulle Express is to receive 8km of new track, and the RER E is to extended by 55km to the west.

This is partly to unload the busiest line in Europe, RER A.

RER B and C traffic is to be cut for five weeks near Massy-Verrières station due to the replacement of the Chartres and Gallardon bridges.

Work around RER C will include replacing track and signalling devices, that are a 100 years old.

One of the most significant moves in the summer this year will be cutting out services from Gare du Nord towards Mitry-Mory and Charles de Gaulle Airport for four days, which could be scheduled for August according to Le Monde.

It is expected that 2,400 bus trips will need to take place per day.

Regarding the Paris 2024 Games, an extension on line 14 towards Saint-Denis-Pleyel to the north and Orly to the south are the only projects expected to be completed before the event, with others either pushed forward or pushed back during the Games.