It stars David Tennant and Janet Montgomery and is adapted by Dick Clement and Ian La Frenais. The supporting cast includes Ann Eleonora Jørgensen (Pernille from The Killing). From the BBC's website:
A thrilling spy story set in Poland, Paris, London & Berlin in the years leading up to the Second World War. French and German intelligence operatives are locked in a life-and-death struggle on the espionage battlefield.
At the French embassy, the new military attaché, Colonel Jean-Francois Mercier (Tennant), a decorated war hero of the 1914 war, is drawn into a world of abduction, betrayal and intrigue in the diplomatic salons and back alleys of Warsaw.
At the same time, the handsome aristocrat finds himself in a passionate love affair with Anna (Montgomery), a Parisian lawyer for the League of Nations. Their complicated love affair intensifies as German tanks drive through the Black Forest.
Two 90-minute film adaptations of one of Furst’s most acclaimed novels will bring to BBC Four a combination of historically located, intelligent narratives, interlaced with flawed, romantic and utterly compelling characters.
BBC America have released a brief trailer: