The film Orson Welles is showing making in post-war Italy is a real one, "Black Magic" (1949), to which he made a number of uncredited contributions as both writer and director. Welles is played by Danny Huston, the son of one of Welles's oldest and closest friends, John Huston. Although the on-screen Welles seems dismissive of the film, the real Welles often said it was the one which had given him the most sheer fun of his entire career.
The real Orson Welles was tumultuously engaged to the real Lea Padovani for a short time in the late 1940s, and cast her as Desdemona in his film of "Othello", although he never shot any footage of her in the role. He also really did know the gangster Charles "Lucky" Luciano, who, he claimed, pestered him repeatedly to make a film about his life.