Prague doubling as Vienna is incredibly funny because the real life Crown Prince Rudolf, upon whom Leopold was very loosely based, really did spend a lot of his life in Prague. note The Rudolfinum in Prague was named after and opened by him.
Sophie the character shares a name with Rudolf's paternal grandmother, Princess Sophie of Bavaria, and his oldest sister note who died as a toddler Archduchess Sophie of Austria.
In the realm of Black Comedy, but Rudolf's nephew, Prince Leopold Clement, was murdered by his mistress for breaking up with her. The incident was compared to Rudolf's death at Mayerling a few decades earlier.
Playing Against Type: Heavily for Jessica Biel, who found herself typecast as a Ms. Fanservice or Action Girl. She drove to the audition in full costume and lobbied really hard for the role. Despite her performance being well-received, it didn't launch her onto anything major afterwards.
Actor Allusion: To Jacques Tati himself: The Illusionist's name is Tatischeff (Tati's full last name), and at a later part in the movie, Tatischeff stumbles into a cinema showcasing Mon Oncle. Tatischeff's body movements are incredibly reminiscent of Tati's in his roles as M. Hulot.