A Year in Paris by Malaurie Barber

When student Chloe Jones becomes an au pair, all she's looking for is an interesting year abroad in Paris, but she gets more than she bargained for in the Glairon family. While caring for sweet little Clement, Chloe begins to care a great deal for his beautiful but haunted half sister, Laurence, too. But not even the most romantic city in the world can help these two when the family's secrets threaten to destroy them all.