The rough cut of the film ran four hours. In reducing it to two hours, several actors were cut, including Ruth Warrick. She does appear briefly in the restored 133-minute version.
During filming in Paris in October of 1946, the government drained the Seine to remove live bombs and inspect the foundation of a bridge. This resulted in the crew having to improvise the river in the background of some shots.
Ingrid Bergman's salary for "Arch of Triumph" was $175,000 plus 25% of the profits. However, there weren't any.
The additional scenes written for Charles Laughton were filmed in New York City in November 1946, because Ingrid Bergman was then starring in a Broadway production of "Joan of Lorraine".
Irwin Shaw spent five months writing a screenplay, but then quit after director Lewis Milestone wanted him to add a love story. Milestone rewrote the script, which was preferred by the studio and Ingrid Bergman.