The opening of line 15-south of the Paris metro, initially planned for December 2025, is finally postponed to the summer of 2026, due to delays in carrying out the tests, according to the Société des Grands Projets (SGP), which manages the construction site.
Line 15 has problems. The Société des Grands Projets (SGP), prime contractor for most of the Grand Paris Express lines, announced this Thursday, November 28, the postponement of the launch of line 15-south of the Paris metro. Initially scheduled for December 2025, it will finally be in service in the summer of 2026. The cause: delays in carrying out the tests.
An “extreme complexity of the Grand Paris Express, which is primarily due to its size”
“I am very disappointed with the new delay announced again today, for line 15-south, the opening of which is now indicated for the summer of 2026,” exclaims Valérie Pécresse, president of the Ile-de-France region. France, in reaction to the announcement of this new postponement, specifying that “line 15-south was initially planned for 2018 and that its schedule has only been postponed year after year”.
To justify this delay, the president of the SGP, Jean-François Monteils, insisted on “the extreme complexity of the Grand Paris Express, which is primarily due to its size”. “We entered this testing phase relatively recently, in September” instead of July, he told AFP. Specifying that the teams discovered “unexpected bugs, difficulties that we did not entirely anticipate”.
This 33 km line will connect Pont de Sèvres to Noise-Champs via 22 municipalities in Hauts-de-Seine, Val-de-Marne and Seine-Saint-Denis. In total, SGP indicates a cost of 8 billion euros for the line.
“Line 15-sud is extremely awaited by residents of the Ile-de-France region, both the towns south of Paris, but also to desaturate the RER A and B by around 10 to 20%,” laments Valérie Pécresse. The latter therefore calls on the SGP to meet the new deadline announced, because “six months of new delays does not mean we will find ourselves tomorrow with nine months, 12 months or worse, postpone to 2027”.
A project worth 36.1 billion euros
The SGP was initially created as part of the creation of the Grand Paris Express. But a year ago, in December 2023, its missions were broadened, and it is now participating in the creation of the Metropolitan RERs.
For its part, at the end of the project, line 15 should be 75 km long and form a circle around the capital. It will be made up of 36 new stations.
Overall, the Grand Paris Express project includes lines 15, 16, 17 and 18. They will form a network of 200 km of automatic metros by 2031. 68 new stations will be created, spread throughout the Island. from-France. This project, considered “the largest in Europe”, according to Jean-François Monteils, is today estimated at 36.1 billion euros, compared to 22 billion in 2010.
