The construction of two lines in the Grand Paris Express, a major automated metro project, will face delays of at least one year. Lines 16 and 17, which were expected to open in 2027 and 2028, will now be delayed, according to the supervisory board of the Société des grands projets (SGP), the organization overseeing the project. Line 16 was originally planned to open in two stages: the first section from Saint-Denis-Pleyel to Clichy-Montfermeil was set for 2027, followed by a second section from Clichy to Noisy-Champs in 2028. Line 17 had a similarly phased opening, with its first section from Saint-Denis-Pleyel to Bourget Airport scheduled for 2027, and additional sections planned for 2028 and 2030. The delays come amid ongoing challenges in large-scale infrastructure projects, which often face unexpected hurdles such as supply chain issues, technical difficulties, or environmental concerns. These delays could affect the broader timeline of the Grand Paris Express, which aims to ease congestion and improve connectivity across the Paris region. Meanwhile, progress continues on Line 18, which runs south of Paris. The SGP has confirmed it will hand over the first section of Line 18 to the Île-de-France transport organizing authority, IDFM, on October 13. This handover marks a key milestone, as it opens the possibility of opening the first segment of Line 18—between Massy-Palaiseau and Le Christ de Saclay—by mid-December 2026, as previously committed. The second part of Line 18, from Massy-Palaiseau to Olry Airport, is still scheduled for 2027, with a final stage connecting Le Christ de Saclay to Versailles-Chantier planned for 2030. More details about the delays and revised schedules for Lines 16 and 17 will be provided in the coming days. The SGP has not yet given specific reasons for the delays, but such updates are expected to clarify the situation for the public and stakeholders.