Four fire engines and 25 firefighters were called to a shop fire on Milkwood Road in Herne Hill.
A wall running between a ground and first floor was damaged by fire. Around 30 persons left neighbouring flats before the arrival of the Brigade. There were no reports of any injuries.
The Brigade was called at 2226 and the fire was under control at 0123. Fire crews from Brixton, West Norwood and Battersea fire stations attended the scene.
The cause of the fire is believed to be due to electrical arching which ignited insulated material in a wall.