The Northeastern Branch of Line 7
Paris Métro line 7bis runs from Louis Blanc in the west to Pré-Saint-Gervais in the east, serving Buttes-Chaumont and nearby neighborhoods. The roughly three-kilometer underground line originated in the early tunnels and stations extending line 7 into northeastern Paris.
Line 7 initially ran from the Opéra area and divided at its northern end toward Porte de la Villette and Pré-Saint-Gervais. Porte de la Villette–Opéra opened on November 5, 1910, followed by Louis Blanc–Pré-Saint-Gervais on January 18, 1911. RATP’s official opening chronology records 3.059 kilometers for the latter section. It initially remained part of line 7’s branching operation.
Responsibilities of the City and the Operating Company
The works followed the concession system of the early Paris Métro. The city supplied infrastructure including tunnels, cuttings, bridges and station platforms. The Métro company supplied track, electrical equipment, station entrances, vehicles and workshops, and operated services. Dividing responsibilities between municipality and concessionaire linked tunnel acceptance, equipment installation and train-service opening.
Fulgence Bienvenüe led establishment of engineering standards for the early network. In a 1975 technical retrospective, RATP new-works director Lucien Lupiac describes specialist tunnel workers, timber-support workers and masons using relatively simple individual tools, with spoil and materials moved through multiple shafts. This organization characterized contemporary network construction; the Buttes-Chaumont section also required complex foundation treatment.
Supporting Tunnels through Old Quarry Workings
Louis Biette’s engineering account describes line 7 crossing the old “American quarries” between rue Secrétan and place du Danube. Beneath Buttes-Chaumont park, the route passed diagonally through a grid of gypsum workings with voids about eight meters high. Some rock pillars supporting the quarry roof had to be removed. The new tunnel vault therefore bore roughly 25 meters of overburden and part of the load formerly carried by those pillars.
Engineers used a semicircular cross-section differing from ordinary tunnels and greatly thickened the masonry. In places, buttresses transmitted thrust to distant gypsum pillars left standing. Toward place du Danube, the tunnel also lay in loose backfill above the workings. Masonry was strengthened and reinforced, and concrete columns beneath sidewalls sometimes crossed three mined gypsum layers to foundations as deep as 25 meters. Passage depended on restoring reliable load paths.
References: [1]
The Junction Station and the Eastern Loop
At Louis Blanc, the early design placed the divergence within the station to reduce train-conflict risks. Biette explains that trains leaving the common section divided after the platforms. Trains heading toward it first stopped on separate tracks, then merged outside the station. Crossing tunnels were vertically separated, avoiding level track crossings.
The arrangement allowed both northeastern branches to share a route toward central Paris. A loop remained at the eastern end. The official 2013 rolling-stock planning report records eight stations on line 7bis, platforms generally 75 meters long and three stations on the eastern loop served in one direction only. The short route, curves and gradients jointly shaped rolling-stock and operating choices.
Separating Two Traffic Patterns in 1967
By the 1960s, demand on the branches had become increasingly uneven. RATP’s 1967 operating and management report describes rising traffic toward Porte de la Villette, following changes in the district and the presence of a major surface-bus terminus. On December 3, 1967, RATP separated Louis Blanc–Pré-Saint-Gervais from line 7 and began independent operation.
The new line 7bis changed how an existing route was served. Porte de la Villette retained its connection to the main line, while the former branch ended at Louis Blanc and fed neighborhood passengers into it. Journeys toward central Paris now required a transfer there, and capacity on each branch could be arranged according to different demands.
Rolling Stock and Subsequent Maintenance Choices
After separation, line 7bis continued using Sprague-Thomson trains, changed to MF67 stock after 1981, and adopted three-car MF88 sets in the 1990s. The 2013 report lists nine MF88 sets assigned to the line, putting some technology from the Boa experimental train into everyday passenger service.
Maintenance of this small fleet was costly. The report describes aging components, reliability problems and cracks in bodies and door panels, with some maintenance performed directly at Pré-Saint-Gervais station. Vehicle choices for the short line continued to depend on curves, maintenance facilities and the wider Métro network.
References: [5]