A French champagne producer literally hit gold when workers doing up an old building on his property brought down a shower of US coins hidden in the rafters.

Francois Lange, the head of the Alexandre Bonnet champagne-producing firm, in this eastern French village on Tuesday described the treasure trove as one consisting of 497 gold coins -- with a face value of 20 dollars each -- minted between 1851 and 1928 and worth today about 750,000 euros (980,000 dollars).

"One of the workers were attacking the building's ceiling with a crowbar when gold coins started to rain down on him, followed by sacks of gold," he said.

Half the find will go the workers and half to the owner.

The origin of the treasure was not known, but the building, a former grape-drying facility, used to belong to a wine producer who traded with Britain and the United States in the 1930s.

Lange said his firm might produce a special vintage to celebrate the find. (AFP)