Ican say that I now possess all of Old Paris." This extraordinary claim, made in 1920 by the French photographer Eugène Atget (1857-1927), was not as outlandish as it sounds. Writing in a letter to the director of the Institut des Beaux-Arts, Atget was referring to the completion of a lifetime's project: capturing the city's streets, monuments and views in their endless variety.

When he died seven years later, the photographic pioneer left behind more than 25,000 images and 8,500 glass negatives, divided among government institutions and private collectors. This cache of images remains the largest ever produced to document the French capital.