The 24-carat-gold and steel sword, with an ivory handle and long curved blade, was bought for 955,400 euros over the phone "by a mysterious buyer who entered bidding mid-sale," said auctioneer Jean-Pierre Osenat.
The sword was a gift from Saudi King Abdul-Aziz bin Saud to Prince Ahmad Shah Khan in Afghanistan to mark the founding of the Kingdom of Saudi Arabia on May 5, 1932.
The sabre, which has a blade nearly 79 centimetres (30 inches) long, was later sold to a private buyer.
The sabre could be of 19th-century Syrian origin.
"The symbolism of the sabre is important in Arab countries," said Osenat's Jean-Christophe Chataignier.
"To offer a sabre is an act of definite friendship, loyalty, confidence and mutual protection between provider and beneficiary.