"In 1947, in a tiny walk-up shop on rue de la Paix, a cobblestone's throw from the National Opera of Paris, Rose Repetto crafted her first pair of ballet shoes for her son, the dancer and choreographer
Roland Petit" This is from Internet. As far as I konow, "walk-up" means the buiolding with no elevator. But in this case the shop or workshop was on second, third or so on floor, or something...