The photographs in this series were created in several French prisons, following a procedure of methodical recording, in the manner of metric or architectural surveys. They show how these places of detention and surveillance had been conceived as “seeing machines” whose optical system is a defining element. In the exercise yards of the isolation block, the metal bars, cables and nets create perspective viewpoints, by making the eye focus on a wall: from these lines of flight, no escape outside of the frame seems possible.