Map of the network of the Compagnie du chemin de fer de Paris à Orléans (PO, in red) and the general interest networks of other French railway companies (in black) on December 31 1937, eve of the creation of SNCF. This map represents the concession holder de jure, although in some cases a third-person actually operated a conceded line. This map only shows general interest lines, as opposed to local interest lines.
Own work
Shapes of borders, coasts and rivers use data from Geofla 2016 and EGM 2020 databases, published by Institut géographique national under Licence ouverte / Open license from Etalab.