Three new stations planned for line 1

According to Reporterre, three new stations—Les Rigollots, Grands Pêchers, and Val-de-Fontenay—could be built on line 1, with Val-de-Fontenay serving as the terminus. The extension is intended to improve public transport access in the southern parts of Fontenay-sous-Bois and Montreuil, areas that are currently underserved by existing services.

Alternative to overcrowded RER A

Contributors to the consultation view the project as a potential alternative to the RER A, a regional rail network that is frequently overcrowded. Île-de-France Mobilités expects the new line to carry between 80,000 and 90,000 passengers daily by 2040, according to the same source. The estimated cost of the project is 1.7 billion euros, and if approved, construction could begin within four years, with an expected opening in 2040.

Trees threatened near Vincennes forest

The construction site would be located near the Vincennes forest, along the avenue de Nogent, covering an area of about one hectare. According to the environmental group Touche pas à mon bois, the project could result in the cutting down of between 221 and 337 trees, depending on the chosen construction scenario. Île-de-France Mobilités claims it has minimized the impact by reducing the construction site area and the number of trees affected.

Replanting and compensation efforts

The infrastructure director of Île-de-France Mobilités, Arnaud Crolais, stated that three to four trees would be replanted for each tree cut down. This plan is part of an effort to mitigate the environmental impact of the project. However, environmental groups argue that the compensation is insufficient and that the project could harm local biodiversity, especially during heatwaves.

Political and environmental divisions

The project has divided local leaders and environmental groups. The mayors of Fontenay-sous-Bois and Montreuil support the extension, viewing it as a long-awaited solution to improve mobility and promote social justice. Some contributors to the consultation see the project as a way to reduce car dependency. However, the group Touche pas à mon bois and others oppose the plan, citing concerns about environmental damage and insufficient compensation.

New public consultation planned

A new preliminary consultation is set to take place from October 5 to December 11, 2026, under the supervision of the National Commission for Public Debate (CNDP). Three independent guarantors will oversee the process. This phase aims to gather public input on the project, its alternatives, and its environmental effects. Île-de-France Mobilités and the RATP have released a new consultation document outlining the project's progress and supporting studies.