Four fire engines and around 25 firefighters were called to reports of a fire at a hotel in Great Dover Street, Southwark.
Part of a room in a ground floor annex was damaged by fire. Crews also investigated the building's internal extraction system but found no further fire. Around 25 people left the building before the arrival of the Brigade.
The Brigade was called at 1048 and the fire was under control by 1243.
Fire crews from Dowgate, Old Kent Road and Dockhead stations were at the scene.
The cause of the fire is believed to have been accidental and involved electrical equipment.