Their story is interesting in that they do not exist. Certain ceremonial objects from the Coronations of the kings of France have survived: Charlemagne’s sword; Charles V’s Sceptre; the Main de Justice (hand of justice). All of these, kept at the Louvre, were used during the countless coronations of France’s kings, right up until the last one.
But a crown? No. The stones of each crown were removed so that a new crown could be fashioned for each new reign.

After a coronation, the crown was dismantled; the stones were given back to the Treasury and used according to the goodwill of each sovereign: set into their swords, or fastened onto their clothing, as would Louis 14th: therefore only to find himself buckling under the weight of the Crown diamonds during his lattermost public farewell, the reception of the Persian ambassador.

Yes, Crown Diamonds did indeed exist: they were the Royal Treasure. Placed in the furniture depository at Place de la Concorde (Paris) for safekeeping, the three thousand precious stones of the Crown were stolen during the French Revolution: an event I enjoyed describing in my book Le vol du Régent. A third of these were found – amongst them, the largest stones – primarily the ‘Régent’: the most beautiful diamond in the world, still kept in the Louvre.

Diamond-Regent-Mickael of -Greece-jewels-France-Crown

Napoleon, and subsequently Louis 13th and Charles 10th, did use the Crown diamonds a fair amount. ‘Diamonds’, meaning coloured stones as well, were used during the 19th century to create parures with diamonds, rubies, and emeralds. Louis-Philippe did not touch any he considered belonged to the Crown. Napoleon III, however, had numerous Crown diamonds set for his wife the Empress Eugenia. This tremendous treasure was seized when Napoleon III fell.

Several years later, the French Third Republic feared a resurgence of pro-monarchy sentiment.
Therefore, they made three decisions. One decision was cruel, my great-grandfather the Count of Paris, heir to the throne of France, was sent into exile; another decision was stupid and criminal, the ruins of the Tuleries, burned by the Commune – the remaining ‘pieces’ of which were substantial and could easily have been restored – were simply flattened; and lastly, the so-called Crown jewels were auctioned off.
Thus, these precious gems – amassed by so many French kings – went to the auction house.

Many of them have been taken out of their settings since, and others have ended up in private collections, where they remain still.
Some of them, but only a few, found their way back into the Palais des Rois, in other words the Louvre, and we can only hope that others too will follow this path.

by  Prince Michael of Greece