The Irish Georgian Society has said it was never consulted about the removal of four statues from Dublin's Shelbourne Hotel.
The bronze sculptures of two princesses and their slave girls, which have stood outside for more than 150 years, were taken down because of their association with slavery.
The hotel said the statues have been removed "in light of recent world events" and the statues' association with slavery.
The society said that any such works require planning permission, which it believes was not sought.
It has contacted Dublin City Council urging them to address the matter.