The House of Shattered Wings by Aliette de Bodard Roc
Paris has survived the Great Houses War, a War created by the Fallen Angels and their houses. Their blood and their essence has polluted the air. While the citizens continue to live on and fight for survival among their ailing country the war of politics continues on. Something from the past has come to undo House Silverspires, once the leader of the power games now a house in disarray. Something in the shadows is stalking them and killing innocents who come and go. But there are three people who might be able to save it: a naive and powerful fallen angel, an alchemist with a terrible addiction and a seemingly young man from the Far East. But are they powerful enough to undo the sins of the father?