A Bordeaux wine producer has been sentenced to two years in jail and fined €8m (£7.1m) for selling inferior wine under prestigious labels to major supermarket chains.

Francois-Marie Marret, 55, was convicted of blending poor-quality wine with high-end Saint-Émilions, Pomerols and Listrac-Médocs to create the “moon wines” – so called because the plonk was spirited to his operation by night.

This was blended with Marret’s prestigious vintages and sold to clients including supermarket chains Auchan and Intermarché.

Co-defendants in the case included a wine merchant, two wine brokers and three producers of lesser wines.

The fraudulent wines fetched nearly €800,000 in 2011 and 2012 before the ring was busted, according to customs officials.

Marret, who owns three chateaux in the Gironde region, said he would appeal against the verdict, which he said was of “stunning severity”.

“Such a verdict is completely abnormal,” he told reporters. “I never sold anything but wine from my property.”

The wine merchant, Vincent Lataste, was given an 18-month suspended sentence and a €5,000 fine, while his company was fined €30,000, of which half was suspended.

One of the middlemen, who worked at Quali-Bordeaux, an independent quality control body, received a one-year suspended sentence.

The other broker was handed an eight-month suspended sentence.

The growers were given six-month suspended sentences along with fines and penalties of up to €12,500, and the driver who delivered the wines from one chateau to another by night got a four-month suspended sentence.