Tom Everett Scott had never been to Europe, stating: "I hadn't left the country. So it was a really big, brand new experience for me, and I got to work with all these great special effects people and we got to climb all over the Eiffel Tower at night. They would shut it down from midnight to 6 a.m. for our production. I don't know how many people get the opportunity to do that but that was a real thrill. We got to run around Paris in the middle of the night, and as a 26-year-old guy who had never been to Europe, I was just fascinated and felt very fortunate."
The church at the end is called Saint de Loup; "loup" is French for "wolf."
In a scene that was deleted from the movie, it was discovered that the werewolf society had been around for centuries and the werewolf that attacked David Kessler and Jack Goodman in Um Lobisomem Americano em Londres (1981) was once a member.
In an interview, Julie Delpy revealed that she gave such a good performance despite taking on the film purely for the cash, and disliking the experience so much that she avoided doing any other commercial Hollywood movies. Her only other blockbuster to date is Vingadores: Era de Ultron (2015).