Opponents of a proposed extension of Paris Metro Line 1 have gathered in Vincennes, a district in the eastern suburbs of Paris, to protest against the project. The extension, planned by Île-de-France Mobilités (IDFM), the regional transport authority, and RATP, the public transport operator, would extend the line to the Val-de-Fontenay RER station in the Val-de-Marne department. The route would pass partly beneath the Vincennes forest, a historic and natural area. A protest is scheduled for Sunday, October 11. The 5-kilometer extension would add three new stations: Rigollots in Fontenay-sous-Bois (Val-de-Marne), Grands Pêchers in Montreuil (Seine-Saint-Denis), and Val-de-Fontenay. The project aims to improve transportation access for residents in the region. If completed, the trip from Vincennes Castle to Val-de-Fontenay would take about eight minutes. The proposal has drawn criticism over its potential environmental impact. Marie-Noëlle Bernard, president of the environmental group Touche pas à mon bois, which is organizing the protest, has raised concerns about the destruction of trees in the forest. She called the project a "disaster for the environment in a climate emergency," emphasizing that trees help capture carbon dioxide and reduce temperatures. She warned that the project would "destroy an entire living ecosystem: centuries-old trees, animals, and 300 years of history." IDFM has defended the extension, stating that after a public inquiry in 2022 and a negative opinion from the inquiry commission, they have resumed studies on the project. According to IDFM, the number of trees affected would be between 221 and 337, fewer than the 484 estimated in the 2022 version of the plan. The authority also mentioned an ecological compensation strategy, including replanting trees, renovating affected areas, and improving ecological continuity. Marie-Noëlle Bernard, however, rejected this plan, arguing that "nature cannot be compensated" and that replanting would not restore the forest. She added that the compensation would likely involve shrubs rather than trees, and the forest would "never be the same again." The cost of the project has also sparked debate. Environmental groups have criticized the estimated cost of 2.5 billion euros as excessive. IDFM, however, said the adjusted cost, based on 2026 economic conditions, would be around 1.7 billion euros. This includes detailed design studies, construction, and land acquisitions, but not the cost of rolling stock such as trains. A public consultation, organized by IDFM, began on October 5 and will run until December 11, allowing residents to voice their opinions. After this consultation, a public inquiry in 2028 will decide the project's future.