Shoppers at the central London store said they were asked to leave at about 15:30 GMT after a warning about a blaze in the basement of the building.
They were led to streets behind the shop while the fire brigade investigated.
The shop reopened after about an hour with no noticeable damage to the building.
There were no reported injuries.
Hundreds of people were evacuated from Topshop's Oxford Street branch amid reports of a fire on the premises.