The true story of a mother’s battle to bring her son back from Guantanamo Bay premiered to cheers in Berlin on Saturday, as the German filmmakers called for reparations for the family.

“Rabiye Kurnaz vs George W Bush” is one of 18 movies from around the world vying for the Berlinale film festival’s Golden Bear top prize, to be awarded on Wednesday.

The film, which was warmly received at a press preview, is by Andreas Dresen, often called the “German Ken Loach” for his empathetic profiles of working-class people’s struggles.

Murat Kurnaz, a Turkish citizen but life-long resident of Germany, was held for almost five years at the US prison in Cuba before being released without charge in 2006.

The film traces his mother Rabiye’s fight from her row house in the northern German city of Bremen all the way to the US Supreme Court in Washington to win her son’s freedom in the landmark case cited in the title.

But, in what has been described as one of the biggest political scandals since reunification, the German government rejected a US offer to release him despite its vocal opposition to Guantanamo because it feared a political backlash.

Berlin used what Dresen called the “Kafkaesque” legal justification that the Turkish man had lost his residency rights as he had been away for more than six months from Germany -- although this was due to Kurnaz’s imprisonment.

‘The bare minimum’

Dresen, 58, said he had followed the case closely at the time and gave credit to the government of Angela Merkel who, days after taking office in 2005, pledged to work for his return which finally came the next year.

“This is a story of despotism, of torture, of terror, of injustice,” he told reporters.

“But we also found it wonderful to learn that so-called average people can defend themselves against the seemingly invincible forces of the world.”

Dresen said it was “the bare minimum” to expect that “if politicians make mistakes that they admit them”.

“There must be compensation in this case, and also an apology from the German government,” he said.

In the film, Rabiye, portrayed with warmth and humour by Meltem Kaptan, forms a kind of odd couple with the reserved German human rights lawyer Bernhard Docke (Alexander Scheer) as the two take on the US and German establishment.

“There’s a universal aspect to this story because of course every mother in the world fears for her children. Everyone can understand what motivates Rabiye,” Kaptan said.

“She found this unbelievable strength in being a mother, and in her positive approach to life.”

Kaptan said the story also shines a spotlight on the role of Turkish “guest workers” and their descendants in German society.

“It raises the question of to what extent someone is German, and then no longer,” she said.

“Is he only German if he does everything right and is successful? What happens to the young people who are still searching for their identity?”

‘Guantanamo is torture’

Murat Kurnaz, now married with three daughters, lives in Bremen. He and his mother were expected to attend the film’s red-carpet premiere later Saturday.

Since his return, he has written a book about his ordeal and has campaigned to see Guantanamo closed.

“Just being at Guantanamo is torture,” he told AFP in 2014.

The detention centre was created after the September 11, 2001 attacks to house detainees in the US “war on terror” and has been called a site of “unparalleled notoriety” by UN rights experts.

In January, the United States approved the release of five of the remaining 39 men still at Guantanamo.

Ten others, including the alleged mastermind of the 9/11 attacks, Khalid Sheikh Mohammed, known as “KSM”, are awaiting trial by a military commission.