Ole Christian Madsen directs the film, based on a true story. Mads Mikkelsen and Thure Lindhart star.
The film is one of Denmark's largest productions ever, budgeted at Euros 8m, and has already been a box-office hit there, with more than 640,000 admissions.
The story follows two World War II resistance fighters in Copenhagen.
The deal was brokered between general manager - theatrical & broadcast Sara Frain, acquisitions & business affairs manager Kate Edwards and CEO Peter Urie for Metrodome, and Brigitte Suarez for The Match Factory.
Metrodome's Urie said: 'Following on from our recent success with The Counterfeiters, we are absolutely delighted to have acquired this exceptional World War II drama which is also based on real events. This title fits perfectly into our release slate as we continue to grow as a company. We are looking forward to working with The Match Factory for the first time.'
Suarez of The Match Factory added: 'We're very excited that Flame & Citron will be released in the UK by Metrodome, who have a reputation for releasing quality films and realising their full potential.'