"This allows us, without using English, to understand the intricacies of negotiations with these clients," said owner Jean-Luc Thunevin who has seen his sales take off in China.

The Chateau des Tourtes in Bordeaux's Blaye district hires two Chinese interns a year to "facilitate communication" and organize trips to China.

Now even the wine schools are tapping the Chinese market.

Zhou Yuchen, a 28-year-old from Beijing, first came to Bordeaux to obtain a master's degree in finance but she was seduced by the wine industry, landing a job with Cafa to help it open a Beijing unit.

China's consumer patterns are also changing. Whereas the early customers were well-heeled, the country's emerging middle class has acquired a growing taste for the tipple and wants value for money.

"The last time I was back at my parents, our neighbor asked me to give my opinion on the wines he had in his cellar," said Zhou, while Wu said these new wine drinkers want "accountability on prices".

Wine sales were hurt by the country's ongoing anti-corruption drive over the past two years in which Beijing has clamped down on lavish banquets and expensive bottles of wine as gifts, said Vinexpo chief Guillaume Deglise.

But he forecast that China's wine market would return to growth in 2015 and keep expanding rapidly.

"We expect 37 million adults to come to drinking age in China within the next five years. This is actually more than the entire population of Canada," he said at a Vinexpo fair in Hong Kong this month.

France is currently the leading supplier of imported wines to China, with 14.5 million cases in 2013, followed by Australia with 4.1 million cases.