D is the highest colour grade attributed to a diamond, indicating that the stone is completely colourless, and thus extremely rare.
With a drawn-out round of rapid-fire bidding starting at 20 million francs, the necklace was finally sold to a telephone bidder, who wished to remain anonymous, for well above the asking price of 25 million.
But some had expected The Art of Grisogono, which Christie's described as a "masterpiece of unparalleled beauty and exquisite workmanship", to fetch even more.
The biggest diamond
The flawless, D colour 11A type diamond was cut from a 404 carat rough rock which was discovered in February 2016 in the Lulo mine in Angola - the 27th biggest rough white diamond ever discovered.
The rough was analyzed in Antwerp and cut in New York, where a team of 10 diamond-cutting specialists were involved in mapping, plotting, cleaving, laser-cutting and polishing the giant rough rock into a polished, flawless diamond.
The gem was named after Cardinal Mazarin, an Italian cardinal, and diplomat, as well as a great art collector, who served as the chief minister under Louis XIII and Louis XIV, and who bequeathed it and other diamonds to the Sun King in his will.
The pink stone originally dug out of the ancient mines of Golconda in south-central India, sparkled on the crowns of Louis XV and Louis XVI, who was guillotined during the French Revolution.
And it graced the crown of Napoleon I, Napoleon III and Empress Eugenie, among others.
The 163.41-carat flawless D colour diamond, suspended from an emerald and diamond necklace called The Art of Grisogono, sold for 33.5 million Swiss francs ($33.8 million, 28.7 million euros), after taxes and commissions, at the Christie's autumn jewel auction.
This marks "a new world-record price for a D colour diamond at auction," Rahul Kadakia, auctioneer and head of Christie's international jewels division