Six fire engines and around 40 firefighters tackled a fire at a restaurant with flats above on Cockfosters Road in Barnet.
Part of the ground floor restaurant was damaged by fire. Two people left the building before the Brigade arrived and firefighters wearing breathing apparatus led nine further people to safety. There were no reports of any injuries.
The Brigade was called at 0436 and the fire was under control by 0603. Fire crews from Southgate, Barnet, Edmonton, Hornsey and Finchley fire stations attended the scene.
The fire is believed to have been accidental and caused by the radiation of heat from a pizza oven coming into contact with a wall, which caused a smouldering fire.