Originally Posted by
subgrade
My guess is the paint job is supposed to mimic the historical look of the window niches. That would also explain why it's present only on the bottom floors, as originally there were only three storeys. Presumably the white painted cornice between second and third floor separates the original building from the part that was added later.
I suspect, given the history, that the first three floors' windows were quite different from what they were when it was a jail/warehouse, and the paint job is supposed to give the building some character, and, as you say, to blend in the upper floor addition. It's a weird effect in the photograph, at first glance it looks like a cartoon. Thanks! Great find.