Designed by Jules Henri de Sibour, an American architect who studied at Yale,but had a French father and was born in France. Much of the best early 20th century buildings in downtown DC, and along Massachusetts Ave near DuPont Circle, and his country club in Chevy Chase,MD were the work of de Sibour,who died relatively young in 1938.
This photo is of the chimney cap at the south end of the Mass. Ave. facade. Almost all his buildings look like they would have been equally comfortable along any Parisian boulevard.
He was also a jock and clubman at Yale.