Guillaume Musso, the author of the source novel, has declared he liked the film, and praised it for its "poetic, mysterious and dramatic atmosphere", its "constant tension" and its "never-slowing pace".
To find the deep meaning of his film, director/co-writer Gilles Bourdos was inspired by a quote from former French President François Mitterrand, which translates to "Beauty is in the moment, which is something we always find out too late".
In the scene where Nathan approaches an ambulance from behind, his feet are reflected in the shiny metal at the bottom of the vehicle's rear doors. Also reflected are the feet of the cameraman following him.