The line opened in stages starting in December 1977 by connecting two existing suburban commuter rail lines with a new tunnel under Paris: the Chemin de Fer du Nord to the north (which formerly terminated at Gare du Nord) and the Ligne de Sceaux to the south (which formerly terminated at Luxembourg station).

The line faces capacity challenges as a result of sharing a tunnel with RER D trains between Châtelet–Les Halles and Gare du Nord.

The RER B opened in stages starting in December 1977 by connecting two existing suburban commuter rail lines with a new tunnel under Paris: the Chemin de Fer du Nord to the north (which formerly terminated at Gare du Nord) and the Ligne de Sceaux to the south (which formerly terminated at Luxembourg station).

Saint-Denis - Aubervilliers Sénat Colonel Rol-Tanguy Maison des Examens Pont Royal École polytechnique The RER B Line has two service patterns: In any case, the stations from Cité Universitaire to Paris Gare du Nord are served by every single train.

[2] Already proposed in the 1994 Schéma directeur de la région Île-de-France (Île-de-France regional development plan, SDRIF), but without any concrete plans ten years later,[3] the project to extend RER B northeast from Mitry–Claye station to the Dammartin-en-Goële area, serving intermediate stations at Compans and Thieux-Nantouillet, is proposed in Phase 3 (horizon 2021-2027) of the revised SDRIF, adopted by deliberation of the Regional Council of Île-de-France on September 25, 2008.