The sixth film in a creative partnership between writer-director Petzold and his leading lady Hoss (whom Homeland fans will recognise as the main German agent in seasons 4 and 5) is perhaps the best yet.
Jerichow in 2008, which riffed on The Postman Always Rings Twice, and the Stasi-era drama Barbara four years later were both standouts, but Phoenix is in a league of its own: a precisely choreographed chamber piece that treats an aspect of German history that the movies haven't really engaged with - what Petzold calls "after the camp".
When survivors of the Holocaust returned, neither they nor the country they had left was recognisable. Both had to be reshaped, reconfigured and reinvented.
That idea sustains the story told here of Nelly (Hoss), who, when we first meet her, is literally faceless, her head swathed in bandages as she is driven to hospital.
"She's from the camps," the driver, her friend Lene (Kunzendorf) says and a GI soon regrets his suspicious demand to see her face.
The almost offhand efficiency of her reconstructive surgery and the speed of her recovery may seem jarringly implausible; likewise the film's impelling idea that the old boyfriend she seeks out would not suspect who she was.
But if we take a breath and a step back and treat the film as a sustained allegory about Germany's inability to come to terms with herself, it assumes a breadth and depth that mark it out as a masterwork.
The old boyfriend is Johnny (Zehrfeld, who was Hoss' co-star in Barbara), a pianist in the bar of the title - its lurid, neon glow spilling out into the rubble-strewn streets makes it seem like the gates of the underworld.
For good reason, Nelly conceals her true identity from Johnny, introducing herself as Esther; he, struck by her similarity to the wife he believes dead, hits on a scheme to have "Esther" impersonate Nelly so as to liberate the fortune to which she, the only survivor of a wealthy family, is entitled.
To do so, he must remake her, in her own image.
It's a story saturated with irony and rich in metaphorical potential and Petzold, who co-wrote the screenplay from elements of a 1961 French novel The Return from the Ashes, mixes it all into a potent brew before delivering a killer climax.
Hoss, surely the foremost German actress of her generation, gives a powerhouse performance, full of pain and longing, and the use of the Kurt Weill and Ogden Nash classic Speak Low is a masterstroke. Highly recommended.
Verdict: Finely wrought thriller.
Cast: Nina Hoss, Ronald Zehrfeld, Nina Kunzendorf
Director: Christian Petzold Running time: 98 mins
Rating: M (adult themes) In German with English subtitles