Nord-Sud Company

The north–south was the initiative of Jean-Baptiste Berlier, an engineer from Lyon trained at the École Nationale Supérieure des Mines de Saint-Étienne, who had previously attempted to build an underground tubular tramway in 1897.

The charter provided that the costs of construction and rolling stock would be borne entirely by the concessionaire, although in the case of the CMP's lines, the City of Paris had fully funded the network infrastructure.

The concession covered three proposed lines: The Société du chemin de fer électrique souterrain Nord-Sud de Paris (French for "Paris North-South underground electrical railway company", abbreviated to the Nord-Sud company) was created in July 1902 and replaced Berlier and Janicot as the concessionaire.

Despite the delay caused by the CMP's opposition the 6.216 kilometres (3.862 mi) line between Montmartre (Place des Abbesses) and Montparnasse was declared of "public utility" (a key step in the French legal process for authorising construction) on 3 April 1905.

[1]: 86 During early studies, it appears that construction of a deep underground railway as in London quickly proved impossible because of the different nature of the ground in Paris.

The characteristics of the railway provided the specifications are similar to those of the CMP lines in relation to loading gauge, maximum grades and the minimum radius of curvature.

The station names were written in porcelain instead of the enamel plates used by CMP, and directions to the trains were set out in tiles in the roofs of the tunnels.

The completion of the northern end of line A from Jules Joffrin to Porte de la Chapelle was then delayed by the outbreak of World War I.