Four fire engines and around 25 firefighters were called to a fire at a flat on Jackson Road in Islington.
Part of a three-roomed flat on the first floor of a three-storey terraced building was damaged by fire.
The Brigade was called at 1021 and the fire was under control at 1132. Fire crews from Kentish Town, Islington and Stoke Newington fire stations attended the scene.
The cause of the fire is believed to be the unsafe disposal of a cigarette.