Auber is a station on Line A of the RER in Paris, France. Opened on 23 November 1971 it was at the time the largest underground station in the world, and represents a feat of underground engineering. The station comprises a main train hall with a superposed ticket hall, together with an extensive network of particularly spacious tunnels connecting to the neighbouring métro stations Opéra, Havre-Caumartin and Saint-Lazare, as well as Haussmann - Saint-Lazare on the RER Line E.