Six fire engines and around 40 firefighters were called to a fire at a flat above a shop on Upper Tooting Road in Tooting.
Part of a second floor flat was damaged by the fire. There were no reports of any injuries.
The Brigade's fire investigators believe the fire was accidental and involved a candle.
A London Fire Brigade spokesperson said: “It’s really important you never leave candles unattended and keep them away from anything that could catch fire such as curtains, furniture or clothes.
"We recommend swapping traditional candles for LED flameless ones as they are much safer, but if you do use real candles, follow our simple safety tips."
The Brigade was called at 1309 and the fire was under control by 1423. Fire crews from Wimbledon, Wandsworth, Brixton, Clapham, Mitcham and Battersea fire stations were at the scene.
Candle safety tips