While the Americans feel they are unfairly locked out of a market, the French feel that centuries of careful cultivation is being thrown up for grabs.
"There would not be a level playing field," Gapenne said.
While French chateau bottles find their origins in wines made at the estate from grapes belonging to the chateau, the U.S. definition for export would use less stringent conditions on provenance. It could include grapes from "vines that have been traditionally used by this wine producer or producer group."
"We think the definition we presented is fair and reasonable," said Greene of the U.S. "The definitions we put forward, we believe accurately reflect what we think the market place can stand and what consumers can understand."
For the French, the very francophone origins of the "chateau" name argue differently.
"The Americans could create 'chateau' wines from grapes from all over and prices would of course be much lower," Gapenne said. "The consumer would be buying a 'chateau' wine with the idea of quality that represents our definition" while in fact it doesn't, he argued.
Several dozen premium wineries in the United States have already used the 'chateau' and 'clos' designation in the past. They were allowed to export wines bearing such labels for three years in the wake of a 2006 trans-Atlantic wine agreement, but that loophole was closed in 2009.
Names and denominations of origins have often created trade friction, affecting everything from Greek feta cheese to Lebanese hummus. In the 2006 agreement, for example, the EU said it was able to contain the use of such terms like Champagne and Port in the United States.
Any dilution of the typical French winery terms would undermine their standing in the world, said Gapenne.
And once the United States breaks the French hold on the term in Europe, it would set a precedent.
"It would become extremely difficult to stop other producing countries" from using the term, Gapenne's FGVB said in a statement. "The notion would be totally discredited and empty of any meaning."