Based on a true story.
According to director Xavier Giannoli an important civil works enterprise first proposed its help for finding a location, then abandoned. The movie was saved at the last minute by a civil-work material renter who proposed its help, its material and its workers to build the 2-km long where most of the film takes place.
According to François Cluzet, director Xavier Gianolli behaved like a dictator, and no one in the crew could bear him.
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