Shadows on the Bayou — Patricia Vaughn

Between a man and a woman, there can be an arrangement...
A young woman of color in 1800s French New Orleans had one destiny--to become the mistress of a rich Creole gentleman. For Sylvia Dupont, her exquisite beauty was a curse. She attracted males like moths to a flame: she was perfection, but her comeliness brought her only despair. Although none of her ancestors were slaves, she was in bondage--for her fate was to be a man's amusement, never his wife. All too soon one of the city's wealthiest, most sophisticated men offered a handsome sum for this customary arrangement....

or there can be love
Sylvia had been willing to accept her fate until Justin Reynaud crossed her path. His golden bronze skin made him forbidden. His kisses made him irresistible. Drawn to him like a bee to honey, she was compelled to join him in a tumultuous union, and trade the luxurious life of the quadroon for the ecstasy of his passion. But the past, not so easily escaped, reached out to repossess her, destroying Justin's trust, and sweeping Sylvia into a desperate struggle between the chains of tradition and one glorious chance to love.