Four fire engines and around 25 firefighters were called to a fire at a flat above a shop on High Road in Wood Green.
Part of a split-level flat on the first and second floors of the building was damaged by fire. There were no reports of any injuries.
A London Fire Brigade spokesperson said: “There were smoke alarms fitted inside the affected flat, but they didn’t raise the alarm.
“This incident is a reminder about the importance of ensuring you have working smoke alarms in every room where a fire could start in your home, plus a heat alarm in the kitchen. Make sure to test them regularly.”
The Brigade was called at 2206 and the fire was under control by 2325. Fire crews from Hornsey, Tottenham and Southgate fire stations attended the scene.
The cause of the fire is under investigation by the Brigade and the Metropolitan Police Service.