Nobu London, situated on the ground floor of the hotel, closed for dinner service as a precaution with diners redirected to Nobu Berkeley Street while firefighters made the area safe.
Six fire engines and 35 firefighters attended the fire at 17:12 with the fire brought under control by 18:30 and guests allowed back in. It is not known what caused it.
London Fire Brigade station manager Clive Robinson said: "The fire was affecting a working platform on the first floor level of scaffolding. A small amount of the external fascia was damaged by fire.
“Around 180 residents and 120 members of staff evacuated before the arrival of the Brigade, fortunately there were no injuries.
“Firefighters will remain at the scene carrying out salvage work inside the property on the ground and first floor.”
The Metropolitan by Como was open as usual this morning and a statement issued by Nobu London said it was expected to re-open for lunch today (4 March).