What was he thinking?

"Boulevard du Temple", taken by Louis Daguerre in late 1838 or early 1839, was the first-ever photograph of a person. It is an image of a busy street, but because exposure time was over ten minutes, the city traffic was moving too much to appear. The exception is a man in the bottom left corner, who stood still getting his boots polished long enough to show up in the picture.

So this was the first man every photographed, I wonder what memory of his was captured in this photo.