(A costume that let an Edwardian gentlemen be colorful and glittery yet still feel masculine!)
Red velvet jacket ornamented with gold; white shirt, red tie, striped sash over a vest of blue cloth, and breeches trimmed with gold braid. Brown stockings, brown hat with red pompon, brown cape.
Click the illustration at left for a larger view.
Source:
Masquerades, Tableaux and Drills. New York: The Butterick Publishing Company, 1906.
Eleven years later, in 1917, Renoir painted the art dealer and patron Ambroise Vollard dressed as a toreador, as seen at right (click to enlarge), though I don't know whether the costume was for a particular fancy dress occasion or merely for the sake of an interesting portrait.