The first stone on the city hall, seen here as as scaffolding around two towers far right in the picture, was laid with royal attendance in 1931. But building did not begin until 1933. In November 36, the "raw building" was finished, then there was no no need for any more scaffolding except for the artistic decorations. Some rooms was taken in use before the war, and all were in use by 1947, though the building was not publicly declared finished before 1950. So, sometime after 1933, and before 36 must the photo have been made.