The Paris Spy by Susan Elia Macneal (Maggie Hope series Book 7)

This is the seventh installment of the Maggie Hope series

Summary
-Maggie Hope, now working for the Special Operations Executive as a spy, is once again on a new mission. She is travelling to the City of Lights, Paris, France. She has learned that her half-sister, Elise Hess, has been released from the all-female Ravensbruck camp, but has disappeared. In the meantime, she can investigate the disappearance and eventual capture of her fellow SOE agent Erica Calvert. She must keep her wits about her as she infiltrates the highest levels of Nazi security to root out a traitor, find her half-sister and find her fellow agent.