A historical and political inquiry into the architecture of the Paris Métro system, from the initial designs of Hector Guimard to recent transformations. Guided by the ‘psychogeographic’ theories of the Situationist philosophers, Chloe Brenan traces, in limpid images, both the forbidding social controls imposed by this built structure, and the freer ‘desire lines’ created by its daily users. Is it possible to reclaim and redefine the city space?