Strangled in Paris

the long version

"Lame recluse Corentin Jourdan rescues an attractive young woman, Sophie Clairsange, from a schooner wrecked during a powerful storm on the Normandy coast. After Sophie recovers from her ordeal, she heads to Paris, followed by Jourdan. About a month later in Paris, Martin Lorson, a professional stand-in for a variety of workers in need of a break, is serving one night as a watchman at the La Villette meat market, where, to his horror, he witnesses a man strangle a masked woman. The crime attracts the interest of bookseller and sleuth Legris, who's tantalized by the one clue left behind by the killer: a medallion with an engraving of a unicorn."--Publishers Weekly. the significance of the black