Murder in the Latin Quarter (Aimee Leduc #9) by Cara Black; 2009. Hardcover

The ninth book in Cara Black's Aimee Leduc series set in Paris sees a Haitian woman arrive at Leduc's office claiming to be the detective's sister - her father's illegitimate daughter. Thrilled at having discovered a relative, Aimee accepts her. But soon she finds herself involved in murky Haitian politics and grisly murders on the Left Bank, the Latin Quarter of Paris.