Political cartoonist Aurel (Aurélien Froment) makes his feature directing debut with this heartfelt and political animation set in a 1939 concentration camp. Not a German one, however: when half a million Spanish refugees fled across the French border to escape civil war – an event known as La Retirada – the French government forcibly contained them within a series of camps. Deemed ‘foreign undesirables’, men and women alike were detained in freezing conditions with little support or medical aid. Men dug themselves holes in the ground in which to sleep. Thousands died of exposure. French gendarmes and Senagelese soldiers were reported beating Spanish prisoners to death for sport. When Germany invaded France later that year, the persecution of the Spanish continued. It is a human rights atrocity, but one largely forgotten – overshadowed as it was by even worse acts in Nazi Germany.

One of the real-life refugees to flee Franco’s Spain was Catalan artist Josep Bartolí (Sergí Lopez), and his experiences provide the focus of the film. His struggles to survive in the camp are seen through the eyes of Serge (Bruno Solo), a mild-mannered French gendarme with whom the inhumanity and brutal torture does not comfortably fit. It is a multi-layered and hugely effective set-up for a story: part tale of friendship, part artist biography, and part much-needed history lesson.

Bartolí’s sketches from his imprisonment inform the visual style of the film – and provide an easy justification for animating the story rather than play it out in live action. The horrors become slightly easier to digest, and Bartolí’s own personality and politics infuse the screen very effectively. Aurel uses a surprisingly limited style of animation, with some scene rendered in an abstract and static fashion. It presents a small challenge in the film’s opening scenes, but soon settles down into a deeply effective aesthetic. In many respects it echoes Singaporean animated film Tatsumi (2011), in which director Eric Khoo adopts manga-ka Yoshihiro Tatsumi’s own style to adapt his short stories. It is realised to superb effect.

The film’s main narrative is book-ended by Serge as an terminally-ill old man (Gérard Hernandez), recounting his experiences to his grandson (David Marsais) – himself an aspiring young artist. It adds yet another layer to a rich, varied story.

It would be easy to wallow in the inhumanity of the camps, but through small moments of humour, hope, and happiness Josep manages to generate a truly humanistic work. The events of Bartolí’s imprisonment bring sorrow; his art brings joy. The film covers both, and everything in between.