The soapstone seal, the 9.2cm-high replica of a mountain with landscapes engraved on its sides, was valued at 500,000-600,000 euros but will cost 1.225 million euros once expenses are added to the sale price.
The successful bidder was Chinese and beat five competitors, three of whom attended the sale at the Primardeco auction house on Saturday.
Each participant had to pay a deposit of 45,000 euros.
Nobody was authorised to use the seal except Emperor Qianlong (1736-1795), who, apart from being wealthy and militarily powerful, was a painter and poet.
He had about 50 seals and used this one for his paintings and poems, according to auctioneer Jérôme de Colonges.
It was put up for sale by a French family who had owned it since the 19th century.
Last December, at an auction in Paris, a Chinese bidder bought a seal from the same period for 21 million euros, a world record at the time.
In 2010 another Qianlong seal fetched 3.386 million euros in Toulouse, while one owned by his grandfather, Emperor Kangxi, was sold for 5.4 million euros in 2008.