in the Vaugirard workshop. To improve the connection of the lines and facilitate the transfer of the carriages, a new link was built in 1935, between the Montparnasse station and the Vavin station of line 4. On 12 July 1928, the Seine general council decided to extend the Métropolitain by , taking it beyond the limit of Paris so that line A would serve the town of Issy-les-Moulineaux with two new stations. Work began in 1931 and led to the relocation of Porte de Versailles station further from the city, the new station being set up with two platforms staggered by . The platforms of the old station were removed and sidings were installed to house trains not in use. The extension comprised only two stations with long platforms, terminating at standard two track station, followed by a reversing area. On 24 March 1934, the southern extension to Mairie d'Issy was inaugurated, the same day as that of line 1 to Château de Vincennes. On the night of 20 April 1944, during the Liberation of Paris, the freight station of Porte de la Chapelle and the RATP central workshop on rue Championnet were bombarded. The former, which is also the line's terminus, was severely damaged though hasty repairs returned it to service a few days later. The line was equipped with a centralised control room in 1971. In 1977 the use of MF 67 rolling stock allowed the inauguration of Automatic Train Control on Line 12. A project to extend the line northwards began in 2007. The first phase of the extension is to Front Populaire, which was opened to the public on 18 December 2012. A further extension, via Aimé Césaire to Mairie d'Aubervilliers, opened on 31 May 2022. Time-line 5 November 1910: Line A of the Nord-Sud company was opened from Porte de Versailles to Notre-Dame de Lorette. 8 April 1911: The line was extended northbound from Notre-Dame de Lorette to Pigalle. 31 October 1912: The line was extended from Pigalle to Jules Joffrin. 23 August 1916: The line was extended from Jules Joffrin to Porte de la Chapelle. 1930: The Nord-Sud company was bought by the CMP company. Line A became line 12. 24 March 1934: The line was extended from Porte de Versailles to Mairie d'Issy. 18 December 2012: The line was extended from Porte de la Chapelle to Aubervilliers - Saint-Denis - Front Populaire. 31