In the early fifties, painters went out of their workshop to tear posters, a few years later, composers started integrating in their works urban sounds they had recorded. In making the city a store of materials, these « affichistes » and electroacoustic composers have profoundly changed our view of it. They made us carry an aesthetic judgment on what appeared to be only a nuisance. They have thus contributed to the aestheticization of the urban space and to the discovery of the beauties of the urban « canaille ».