With the passing of the years, each neighbourhood, each street in a city evokes a memory, a meeting, a regret, a moment of happiness for those who were born there and have lived there. Often the same street is tied up with successive memories, to the extent that the topography of a city becomes your whole life, called to mind in successive layers as if you could decipher the writings superimposed on a palimpsest. And also the lives of the thousands upon thousands of other, unknown, people passing by on the street or in the Métro passageways at rush hour.