This antique stick pin is from Harry's New York Bar in Paris, Trap No. 1.  It is brass and white enamel depicting a Fly, known as the International Bar Fly from Harry's.  The IBF was established around 1924 as a lighthearted secret society for serious drinkers who frequented there. Many renowned figures, authors, Hollywood stars were regulars.  Famous members from back in the day were: Ernest Hemingway, F Scott Fitzgerald, George Gershwin and Humphrey Bogart. Hard to see slight marks on the enamel.