Gardien du Temple is an interactive installation where the concealment or revelation of poems and images is achieved through diminished reality, a new approach to augmented reality using a projector-camera system. By capturing the environment with a camera and canceling parts of the scene by reprojecting inverted images, Gardien du Temple questions the control of our perception, of what is present or not. It reveals new perspectives for installations and performing arts aiming at erasing parts of the physical space.