Andana Films has boarded worldwide sales on “ Detention ” (“La Détention”), Guillaume Massart’s second feature, ahead of its world premiere in the ACID sidebar at the Cannes Film Festival later this month. The French documentary is set inside the country’s prison officer academy, where the film observes trainees as their language, movements and certainties gradually align with the institution around them. Céline Loiseau of TS Productions produced. Popular on Variety “We couldn’t have dreamed of a better premiere for this film than being part of the ACID Cannes selection,” said Loiseau. “The film is an immersion into the training of prison guards; through it, Guillaume Massart dives into the heart of the carceral system, yet keeps the prison itself off-camera, revealing the society that builds it.” “We have been following Guillaume Massart’s work for a long time,” said Stephan Riguet of Andana Films.…