PARIS (AP) — Four Paris auctioneers and dozens of auction workers are going on trial accused of a vast and long-lasting scheme to steal thousands of pieces of artwork and other valuable items.

The works were meant for sale at an esteemed 19th-century auction house, and include a Courbet painting, Chagall and Matisse lithographs, and a 2.08-carat diamond.

About 50 people working at the Hotel Drouot, the biggest, oldest and most famous auction house in France, are appearing in a Paris court on Monday charged with gang-related theft, conspiracy to commit a crime or handling stolen goods.

They face up to seven years in prison and 175,000 euros ($195,000) in fines each if convicted of all charges.