Museum researchers say they spotted the ancient Egyptian objects, allegedly looted from Egypt, in the latest catalogue listing antiquities for sale by Christie's Auction House.
Six artifacts in the catalog are listed as having been in a private British collection since he 1940s.
"But I had reason to doubt this," Marcel Maree, the museum's Assistant Keeper of Ancient Egypt and Sudan Department, told Ahram Online.
Maree contacted archaeologist Hourig Sourouzian, a member of an extensive network of Egyptologists who help the museum trace the provenance of possible stolen antiquities.
Sourouzian, who has been conducting excavations at the Amenhotep III mortuary temple on Luxor's west bank, immediately recognized the red granite relief fragment depicting a Nubian captive, a motif often found at the bases of large royal statues.
Searching through an archaeological database, she confirmed the fragment was discovered at the temple in 2000.
"We are now researching the possible origins of the other five," Maree said.
All six pieces would remain in the possession of Christie's Auction Hall until British police investigations identify the owner, he said.
"We have no reason to trust the '1940s' collection history claimed for the other pieces consigned to Christie's by the same individual," he said.
"Stopping the looting and smuggling of Egyptian antiquities is not an easy job."