The hotel scenes were filmed at the Avenida Palace hotel in Barcelona. The Beatles stayed there in the Master Suite, Rooms 109-110-111, while giving their only concert in Barcelona at the Plaza de Toros Monumental on July 3, 1965.
Much of the film's background information, such as the story of Brian being beaten, robbed and blackmailed after soliciting a man at a men's toilet, is taken directly from the 1983 book "The Love You Make: An Insider's Story of the Beatles" by Peter Brown and Steven Gaines.