Being an architect in Cincinnati, I have some info on the buildings in the picture: The farthest in the background is the Carew Tower (still standing, started in 1928, completed in 1931), which was designed by the same architects as the Empire State Building, built by the same contractor, and also served as the prototype for the ESB. The people are lined up north-south, facing south on Walnut Street. The parade is most likely on Fifth Street, which the people are facing. The building the people are lined up against is the Potter Stewart United States Courthouse (still standing, completed 1939?). I don't know the building on the left, which had been demolished prior to my moving to town. There was a classic movie palace called the Albee Theater (demolished) between the mystery building and the Carew Tower which is not visible.
BTW - Carew Tower is not the first structure in Cincinnati that served as a prototype for an important New York structure. The Brooklyn Bridge (1883) was built after John A. Roebling designed and built a suspension bridge first in Cincinnati in 1866 (still in use).