The Paris Winter by Imogen Roberston
Quietly starving, and dreading another cold Paris winter, she stumbles upon an opportunity when Christian Morel engages her as a live-in companion to his beautiful young sister, Sylvie. Maud is overjoyed by her good fortune. With a clean room, hot meals, and an umbrella to keep her dry, she is able to hold her head high as she strolls the streets of Montmartre. No longer hostage to poverty and hunger, Maud can at last devote herself to her art.
But all is not as it seems. Christian and Sylvie, Maud soon discovers, are not quite the darlings they pretend to be. Sylvie has a secret addiction to opium and Christian has an ominous air of intrigue. As this dark and powerful tale progresses, Maud is drawn further into the Morels' world of elegant deception. Their secrets become hers, and soon she is caught in a scheme of betrayal and revenge.