French designer Coco Chanel spied for the Nazis during the German occupation of France in World War II, according to a new book on sale Tuesday.

"Sleeping with the Enemy: Coco Chanel's Secret War," by Hal Vaughan, expands on long-standing evidence that the iconic designer had a double life and was the lover of a spy, Baron Hans Gunther von Dincklage.

"Sleeping with the Enemy pieces together how Coco Chanel became a German Intelligence operative; how and why she was enlisted in a number of spy missions; how she escaped arrest in France after the war," New York publishers Knopf said in a statement.

Vaughan's book reveals that not only was Chanel recruited to the Abwehr military intelligence organization, but that von Dincklage was himself a "Nazi master spy."

He "ran a spy ring in the Mediterranean and in Paris and reported directly to Nazi propaganda minister Joseph Goebbels, right hand of Hitler."

Chanel was also "fiercely" anti-Semitic, the book says, although at the time she would not have stood out among numerous other high-profile compatriots later seen as having collaborated during the 1940-44 occupation.

Chanel, an orphan who became a revolutionary fashion designer, moved to Switzerland after the war before returning to Paris to take up her career in fashion. She was never charged with any wrongdoing and died in 1971.