This comes from a Daguerreotype taken by Daguerre himself in 1838. It is probably a picture of a man (on the left) getting his shoe shined by a shoe shiner (in the right, less distinct). The image would have been exposed for about ten minutes, so the crowds wandering around on the street, carriages, etc. would be visible in this photograph as nothing other than a virtually undetectable fog as the occasional photon-chemical interaction would occur.
To see the original photograph, of the Boulevard du Temple in Paris, and learn more about this photo, visit The Hokumburg Goombah.