- Acting for Two: Claude Rich plays two parts: General Leclerc, with a moustache, and Lt. Pierre de la Fouchardière, without a moustache. He is credited at the end only with the part of Leclerc. His role as the young lieutenant is not by chance: Rich, as a teenager, was watching soldiers in the street when the real-life Pierre de la Fouchardière called him into a building to protect him.
- All-Star Cast: A la The Longest Day in this regard. It stars Kirk Douglas, Glenn Ford, Gert Fröbe, Orson Welles, Anthony Perkins, Robert Stack and a huge bunch of high-profile French actors of the time, including Charles Boyer, Michel Piccoli, Jean-Pierre Cassel, Yves Montand, Leslie Caron, Jean-Paul Belmondo, Simone Signoret, Claude Rich, Bruno Cremer, Daniel Gélin, Alain Delon, Sacha Pitoëff, Pierre Vaneck, and Jean-Louis Trintignant. A young, pre-fame Patrick Dewaere was also there, as a Resistance extra.
- Deleted Role:
- Executive Meddling: According to screenwriter Francis Ford Coppola, Charles de Gaulle's government strictly controlled the film's production (pretty much the same way TV content was controlled by the ORTF). The latter would only permit location filming in Paris (which was, of course, crucial) if his rules were obeyed to the letter. In particular, he was anxious to minimize the part played in the Liberation by the French Communist Party; it was, said Coppola, blatant political censorship.
- Fake Nationality: Orson Welles as a Swedish consul.
- Hostility on the Set: Orson Welles repeatedly clashed with director René Clément, refusing to speak directly to him despite being fluent in French. Reportedly, Welles was upset that Clément had been given such a large budget for a project, while he had been struggling to find financing for his projects.
- Irony as She Is Cast: The Jewish Kirk Douglas portrayed General George S. Patton, who was rabidly antisemite in private.
- Multiple Languages, Same Voice Actor: The film's script was written in three different languages, and all the actors spoke their dialogue in their own languages (i.e. the French actors spoke French, the Americans spoke English, and the Germans spoke German), then the film would be dubbed into a single language depending on where it was released. Most of the French and German actors did their own dubbing, because many of them were bilingual.
- Typecasting: Adolf Hitler is played by Billy Frick, a Swiss-born character actor whose entire career was predicated on the fact that, under a wig and the right grooming, he bore an uncanny resemblance to the real Führer.
- What Could Have Been:
Trivia / Is Paris Burning?