The film was shot over 11 of the hottest weeks of the year. Toward the end of the schedule, Burt Lancaster took time out to pick up his Best Actor's prize for Birdman of Alcatraz (1962) at the Venice Film Festival.
There is much kissing of hands during the movie. According to the book "Histoire de la politesse de 1789 à nos jours (History of good manners from 1789 till today)" by F. Rouvillois, the kissing of hands only appeared at the turn of the XXth century when the story in the movie was supposed to take place in 1860-1862, more than 40 years before.
In the first scenes of the movie, Burt Lancaster goes to his girlfriend's home, who is about 40 year's old in 1860, but she has a vaccine scar on her left arm. The first vaccine was found in 1885 by Louis Pasteur.