The owner of Edinburgh's Jenners building has begun an investigation after signs bearing its name were removed from the landmark shop.
Witnesses spotted the distinctive gold-coloured lettering being taken down on Wednesday.
A spokesman for the Danish billionaire Anders Holch Povlsen, who owns the listed building, said they were "very surprised" the signs had been removed.
Frasers Group, which operates the store, has been asked for comment.
City of Edinburgh Council said it was also investigating whether the removal of the signs was a breach of planning rules "given the historical significance of the building".
"We'll take action if appropriate," Neil Gardiner, the planning convener added.
The Jenners building has occupied a prime location on Princes Street for 183 years.
It was bought by Mr Povlsen - who is one of Scotland's biggest landowners - in 2017, reportedly for £53m.
The store is currently operated by the Mike Ashley's Frasers Group, which owns the commercial rights to the Jenners trading name.
It said it would be quitting the site in May after the two sides were unable to come to an agreement.
Frasers Group includes Sports Direct, House of Fraser and Evans Cycles.
Anders Krogh Vogdrup - the director of AAA United, which owns the Jenners building - told BBC Scotland: "We are very surprised seeing the signage being taken down. We are convinced that the signage is part of the listed building.
"We have not discussed any such step with Sports Direct, and certainly not given any authorisation to do so. We will look in to this matter, contacting Sports Direct.
"We can only once again emphasise that the Jenners building of Edinburgh is an institution and, despite the changing face of retail, it is our aspiration that there will continue to be a retail store for as long as we are its stewards.
"Our involvement in the Jenners building, is first and foremost about helping to preserve a unique historic building in Edinburgh. Already when we acquired the building, we knew that it came with a great deal of responsibility.
"Jenners is an iconic building in Edinburgh, and we take the responsibility very seriously. "
The building owner is currently in advanced talks with a new tenant to move into the department store.