This is Kleinert's first feature film for almost ten years since his Paths In The Night (Wege In Die Nacht) which opened Cannes Directors' Fortnight in 1999.
In the intervening period Kleinert had worked on several TV movies for German television.
Based on a screenplay by Thomas Wendrich, Head Under Water centres on a loner and outsider (played by rising young star Frederick Lau) who strikes up a friendship with his German teacher (August Diehl) as they share a common passion of minature modelling and making dolls. But when Rico's teacher suggests they make a life-size doll of the prettiest girl in school, Rico realises that there is something deeply wrong with the man who had become a kind of substitute father for him.
The cast of the Typhoon AG production also features Devid Striesow and Alice Dwyer.
In other sales news, Philippe Tasca's young Paris-based Rendez-Vous Pictures has picked up the international rights for Stefan Westerwelle's feature debut While You Are Here (Solange Du Hier Bist), which had its world premiere in Locarno last year.
The film, about a lonely and isolated old man and a young male prostitute, received a Special Mention in the competition for best debut in Locarno.