The house of shattered wings - Aliette de Bodard

Paris in the aftermath of the Great Magicians War. Its streets are lined with haunted ruins, Notre-Dame is a burnt-out shell, and the Seine runs black, thick with ashes and rubble. Yet life continues among the wreckage. The citizens retain their irrepressible appetite for novelty and distraction, and The Great Houses still vie for dominion over France's once grand capital.
House Silverspires, previously the leader of those power games, now lies in disarray. Its
magic is ailing; its founder, Morningstar, has been missing for decades; and now something
from the shadows stalks its people inside their very own walls.
Within the House, three very different people must come together: a naive but powerful Fallen, an alchemist with a self-destructive addiction, and a resentful young man wielding spells from the Far East. They may be Silverspires' salvation; or the architects of its last, irreversible fall . . .