Fifi D'Orsay was born Yvonne Lussier in Montreal in 1904, the daughter of a postal clerk and went on to become one of the best-known Montreal female entertainment exports until Megan Calvet. She was one of 12 children and moved to New York to do vaudeville and then appeared in a bunch of films, pushed as the French Bombshell. In fact she was neither bombshell nor French as she wasn't much of a looker and was quite open about being from Montreal and often boasted that she had never seen Paris. She died in Los Angeles in 1983.
Montreal was full of nightclubs in the 1940s as Christopher Plummer describes in this interview about his younger days in the city. He notes that Sinatra would drop in to watch Mabel Mercer, whose vocal techniques he is said to have emulated.
Plummer also describes one of the strangest things he's even seen in showbiz, watching an elderly bag lady enter a cabaret in Montreal and insist on singing. It turns out that it was Mistinguett, who impressed the posh room with a version of her tune Mon homme.