The line was the first to open, with its inaugural section entering service in 1900. It is also the first line on the network to be converted from manually driven operation to fully automated operation. Conversion, which commenced in 2007 and was completed in 2011, included new rolling stock (MP 05) and laying of platform edge doors in all stations. The first eight MP 05 trains (501 through 508) went into passenger service on 3 November 2011, allowing the accelerated transfer of the existing MP 89 CC stock to Line 4; however, as of 2019, Line 4 is also being converted to automatic operations. The conversion allowed Line 1 to operate as the system's second fully automated line, after Line 14.