Hotel Elysée was founded in 1926 by Max Haering, and in the late 1930s (1936, we're told) the hotel's new proprietor, Mayer Quain, opened the Monkey Bar just off its lobby, though it wasn't formally named that for another decade or so. While the hotel came first, it's impossible to separate it from its bar
According to the NY Times, the bar, under Quain's direction, was open from 10:30 a.m. to 4 a.m. It featured "naughty" piano acts and lots of booze, and Life Magazine referred to it as "a swank version of a theatrical boardinghouse." It attracted some known names, like the Gish Sisters, Robert Benchley, Isadora Duncan, Babe Ruth, Ava Gardner, Helen Hayes, and Tennessee Williams, who swallowed a cap and died in the hotel, where he had been living for two decades.
Tallulah Bankhead was also a regular, having lived in the hotel with her pet lion cub for some time, and Frank Sinatra, Marlon Brando, and Joe DiMaggio were frequents guests themselves.
Other characters spotted regularly at the bar included the talent, like Johnny Andrews, who played piano there for 50 years. He told the NY Times in the 1990s, "Originally they had live monkeys in there. The Board of Health stopped that immediately. So they got rid of them and painted some on the walls." Whether or not that's true (a publicist could not confirm), the monkey motif remains today.