Joseph Goebbels made sure that the film's print was one of the first things seized by the Germans when they occupied France. He referred to Jean Renoir as "Cinematic Public Enemy Number 1". For many years it was assumed that the film had been destroyed in an Allied air raid in 1942. However, a German film archivist named Frank Hansel, then a Nazi officer in Paris, had actually smuggled it back to Berlin. Then when the Russians entered Berlin in 1945, the film found its way to an archive in Moscow. When Renoir came to restore his film in the 1960s, he knew nothing of Hansel's acquisition and was working from an old muddy print. Purely by coincidence at the same time, the Russian archive swapped some material with an archive in Toulouse. Included in that exchange was the original negative print. However, because so many prints of the film existed at the time, it would be another 30 years before anyone realised that the version in Toulouse was actually the original negative.
Erich von Stroheim clashed with Jean Renoir in the early days of shooting, and the director later said the actor "behaved intolerably." They had one argument over whether or not there should be prostitutes in the German quarters, a detail Von Stroheim thought would lend greater authenticity but which Renoir rejected as a childish cliche. The dispute so distressed Renoir he burst into tears, which caused Von Stroheim to do the same. They fell into each other's arms, and Renoir said that rather than quarrel with an artist he so greatly admired, he would give up directing the film altogether. Von Stroheim promised from that point on to follow Renoir's instructions to the letter, and he kept his word. Looking back on the production, the actor said, "I have never found a more sympathetic, understanding and artistic director and friend than Jean Renoir."
The little girl who played "Lotte" never saw the film, having died of the flu some weeks before the film was released.
The uniform worn by Jean Gabin was actually owned and worn by Jean Renoir, who served in the air force during WWI.
The movie title "La Grande Illusion" is a reference to the pre-war book "The Great Illusion" by Norman Angell, which argued that war was outmoded, unscientific, and absurd. Though little-known today, it was a tremendous sensation when first published in 1909, and was often cited as evidence that a long European war "could not happen". Renoir aptly picks the title for his own work, knowing that his audience would recognize the reference.