Velvet is the Night

As the newly appointed commissioner, Phillipe Dubet has the power of life and death over the local French aristocracy. In return for her family's safe passage out of the country, the breathtakingly lovely Claire Devereux agrees to be his mistress. She is to live in his luxurious quarters, to be seen with him about town, and to accommodate his desires whenever he wishes. 
Claire surrendered her body to Dubet, but swore he'd never break her spirit. What she didn't know was that the real Dubet had been abducted, and his American twin brother Adam Dillon was installed in his place as a spy. And she was devastated to find that her body was not at all immune to the pleasures of "Dubet's" caress, nor her heart to his intoxicating company.