Six fire engines and 35 firefighters and officers were called to a fire at a house converted into flats in Grosvenor Avenue, Islington.
Part of the second and third floor of the building was damaged by fire. One woman left the building before the arrival of the Brigade and was treated at the scene for smoke inhalation.
The Brigade was called at 1030 and the fire was under control at 1204. Fire crews from Islington, Stoke Newington, Shoreditch, Euston and Soho fire stations attended the scene.
The cause of the fire is under investigation.