Quiz

Originally, author Harlan Coben had optioned off his novel to Hollywood, with Director Michael Apted attached. During this time, Writer and Director Guillaume Canet, who had loved the novel, had been calling up Coben with his take on the novel. Coben was immediately impressed with Canet's passion for the story, and his vision, stating that Canet understood that the novel was a love story first, and a thriller second, which Hollywood never got. When the option with Hollywood fell through, Coben contacted Canet and decided to give him a chance.

Guillaume Canet and Jean Rochefort share a lot with the characters they play. Gilbet Neuville (Rochefort) is a horse breeder and his son Philippe (Canet) is a show jumper. In real-life, Canet was born to a family of horse breeders and was a show jumper with the French National Equestrian Team. As for Rochefort he has been a horse breeder since the sixties, he owns Le Haras de Villequoy, and served as the equestrian events consultant for France Televisions at the 2004 Olympics.

Guillaume Canet recalled that François Cluzet and Marie-Josée Croze threw themselves completely naked into a lake at 5 a.m. while the whole crew was wearing down jackets.

The rider being announced at the equestrian show late in the movie is called Hervé de Luze, which is the name of the editor of this movie.

Alexandre Beck and Margot Beck are seen in flashback as young children by the lake. François Cluzet is actually 15 years older than Marie-Josée Croze...and looks it.

Harlan Coben: The author appears as the tall bald man who follows Dr. Alexandre Beck (François Cluzet) in the station.