Line 1 and Line 4 were conceived as central east–west and north–south lines. Two lines, "ligne 2 Nord" (Line 2 North) and "ligne 2 Sud" (Line 2 South), were also planned but Line 2 South was merged with Line 5 in 1906. Line 3 was an additional east–west line to the north of line 1 and line 5 an additional north to south line to the east of Line 4. Line 6 would run from Nation to Place d'Italie. Lines 7, 8 and 9 would connect commercial and office districts around the Opéra to residential areas in the north-east and the south-west. Bienvenüe also planned a circular line, the "ligne circulaire intérieure", to connect the six main-line stations. A section opened in 1923 between Invalides and the Boulevard Saint-Germain before the plan was abandoned.