Ole Christian Madsen, director of Danish smash Flame & Citron, is modest about the remarkable success of his Second World War epic which has grossed more than $9m at the local box office, and is the most popular Danish film for 10 years.

"I'm surprised it did so well in Denmark," he confesses. "There were a lot of moral discussions about the film, people either loved it or hated it. It was the first time a film has shown the Resistance could do something wrong. I was in the media every day for four weeks."

The story follows two assassins for the Danish Resistance, played by Thure Lindhardt and Mads Mikkelsen, who hunt and kill Danish collaborators and Nazi officers.

Denmark is not the only territory taking notice. The Match Factory has sold Flame & Citron to 25 territories including IFC for the US and Metrodome for the UK (The Times BFI London Film Festival will host the UK premiere). The film was well received in both Telluride and Toronto.

"The great unsolved mystery was how it would work outside Denmark and Europe," Madsen says. "But it's working very well."

The film is a classic case of what could have turned into a horrible Europudding - there are 32 partners on board. "I avoid Europudding syndrome by not reading notes," laughs Madsen, not entirely joking. "There were only two or three main partners (including local outfit Nimbus and Germany's Wuste Filmproduktion) who had any say creatively. As the director, I had to toughen up in that process."

The film had a budget of $8.5m but Madsen points out so many partners ate into the production spend due to lawyers' fees and other partner costs.

Madsen's next project will be more like his smaller, past features such as 2001 film Kira's Reason: A Love Story. The untitled project, about sex addiction, will shoot in Denmark in December or January on a budget of about $1.5m. The story follows a man and woman who meet in rehab. "The tone is a dark, lonely story, like Leaving Las Vegas," Madsen says.

He is also planning a bigger film, Eik & Eben, about the Dutch 1960s beatnik Eik Skaloe. "He was the Danish Jim Morrison," says Madsen. "This is a huge love story and also about longing for freedom."