My guess is this will break auction records.
Some incredible research by Vincent Meylan directly linking them back to the French Queen. Amazing they can be clearly identified on a contemporary painting of the French Queen. The Louvre is probably desperately counting its money as we speak!
They ended up in the Bourbon Parma family after the death of Marie Antoinette's daughter, query whether they were owned therefore by the late Infanta Alicia? Marie Antoinette's famous pearl was amongst her property and auctioned a few years ago.
The jewels that passed through the Bourbon Parma dynasty are incredible.