After studying art in Berlin, Citroen started off as a Dadaist painter. In 1919 he moved to Weimar to study at the Bauhaus, where he was influenced by the teaching of Klee, Kandinsky and Itten. In 1923 he produced Metropolis. At the end of 1920s he focussed on photography and opened a new art school, which shut down just one year later. He taught at the Royal Academy of Art in The Hague until 1960, when he re-started painting portraits.