A woman escaped with a minor foot injury when masonry fell from the front of Selfridges in central London.
Westminster City Council is investigating the accident
Emergency crews were called to the incident at 1230 BST on Friday after a piece of masonry fell to the ground and split, hitting the woman.
She did not need hospital treatment but the front of the building has been cordoned off pending an investigation.
A man died in a similar incident when a rosette feature fell from the Duke Street side of the site in 2002.
"We take the safety of our customers, employees and the general public very seriously," said a spokeswoman.
"Regular checks take place on the building and planned inspections take place every five years."
Surveyors and structural engineers carried out an inspection of the building in February and concluded that no immediate work needed to be done.
Westminster City Council confirmed it would be investigating the accident.