Mystery Building by Raoul Froger Doudemont

We are cataloguing the Raoul Froger Doudemont Collection, and this photograph has us stumped.

Froger Doudemont photographed in New York City and Washington D.C. around the turn of the 20th century--but where is this?

There are no prizes for the solution to this conundrum, just our eternal gratitude and smiles from the gods of metadata. Please use the Comments  box to dazzle us with your scholarship and knowledge of the world.