With her belted jersey dresses, ropes of pearls and jet black hair, Abwehr Special Agent F-7124 - code name Westminster - was possibly the chicest spy the Nazis ever lured on to their payroll. But Coco Chanel, luminary in the fashion firmament of pre-war Paris, was the perfect recruit. She wanted something the Nazis had it in their power to give: the release of her nephew André Palasse, held at a Stalag after the French failed to hold the Maginot Line.
Chanel thought she knew how to navigate Nazi-occupied Paris. She had acquired rooms at the Ritz, requisitioned to accommodate the invading top brass. And she was working the Nazis' Aryan laws to try to push out her Jewish business partners, the Wertheimer brothers Pierre and Paul, from their joint perfume business. But in 1941, with André's freedom on offer, she agreed to accompany the Abwehr agent Baron Louis de Vaufreland Piscatory to Madrid on a spy-recruiting mission. Whether she was a reluctant accomplice acting with instrumental purpose or a convert to the Nazi cause, Hal Vaughan does not say. Perhaps he hopes the facts will speak for themselves?
They are damning enough. Secret police documents he has tracked down show how, two years later, Chanel undertook another mission to Madrid, this time at the behest of the SS agent Walter Schellenberg, Himmler's right-hand man. It was, as Vaughan notes, a "hare-brained" scheme to use her well-placed British connections, as a former lover of the Duke of Westminster (hence her code name) and personal friend of Winston Churchill, to convey the Germans' covert desire for peace talks. Still, you can imagine how a woman as intoxicated by her own power as was Chanel (or, at the very least, as used to getting her way) may have thought herself capable of something beyond the grasp of mere politicians.
In the event, her first mission proved lame, and the second was disastrous. A former muse and fixer of Chanel's, the aristocratic Vera Bate, now Lombardi, attempted to turn her in, only to find herself detained on spy charges and leaving Chanel to plead with Churchill to intercede in her release. What began like a scene out of an Ian Fleming novel rapidly unravelled into an Ealing comedy. This was not the only time Chanel dodged exposure. She was arrested and interrogated by the Resistance in the months after the liberation of France. Luckily for her, the interrogators appear not to have had access to French intelligence reports that would have given them cause to lock her up.
Vaughan suggests that her wartime exploits were underpinned by a visceral anti-Semitism - which the Marie Claire editor-in-chief Marcel Haedrich described as "not only verbal, but passionate . . . and often embarrassing" - and cushioned by her close association with prominent figures willing to co-operate with the Nazis, such as Jean Cocteau and the dancer Serge Lifar. So far, so very French.
In 1940, Chanel embarked on an affair with the Abwehr master spy Baron Hans Günther von Dincklage that would last for more than a decade, persisting through their shared exile in Lausanne. A suave, multilingual playboy of high-born pedigree, Dincklage had run an espionage ring in Toulon before the war and had graduated to SS intelligence.
The affair with Dincklage, 13 years Chanel's junior, is now the stuff of common knowledge. But Vaughan - whose publishers describe him as having been "involved in CIA operations" - has done painstaking work piecing together archive documents and private diplomatic correspondence that argue a much stronger case against Chanel.
The problem is that the book does not add to our understanding of this enigmatic woman. Vaughan is at his best when caught up in his police material, but his rendering of history reads like an A-level primer, and he tends towards a loose style and breathless, bodice-ripping tone when writing about Chanel's sexuality and naked ambition: "Sometimes the kitten, sometimes the vamp, and often the vixen, Chanel's moods shifted." If only he'd used his formidable energy to unpick her motives and calculations, and speculate intelligently on the ways in which enemy occupation can mess with the psyche. As it is, Sleeping With the Enemy reads like an extended piece of journalism. There's nothing wrong with that, if that's where your curiosity ends, but I wanted more.
Yet, even though his narrative lacks finesse, Vaughan brings some fascinating bit players into view - Jewish-German Nazi spies, ardent collabos who walked free. He conjures an era when morality could bend like a circus acrobat; when spies, double agents and black marketeers ruled with impunity and one's friends were willing to forgive almost anything.
After the war, Chanel paid off certain people who might have sunk her, including Schellenberg, and for the most part her friends in the Resistance, such as the poet Pierre Reverdy, generously pardoned her crimes. Her collaboration was glossed over - à la guerre, comme à la guerre - and then forgotten. Lately, however, it has been denied, and nowhere more loudly and vigorously, as one might expect, than amid the soft-carpeted corridors and humming tills of Chanel Inc on the rue Cambon.
Sleeping With the Enemy:
Coco Chanel, Nazi Agent
Chatto & Windus, 304pp, £20
Marina Benjamin is the author of "Last Days in Babylon: the Story of the Jews of Baghdad" (Bloomsbury, £9.99