New Delhi, June 15 -- EVIAN-LES-BAINS - The bottles of Burgundy and Bordeaux sitting in American restaurants and wine shops have become, over seven years, a kind of diplomatic hostage. Donald Trump reaches for them whenever France does something he does not like.

On Monday, as world leaders gathered in the French lakeside town of Evian-les-Bains for the G7 summit, Trump told the New York Post that he would impose 100 percent tariffs on all French wines and champagne unless Paris eliminates its 3 percent digital services tax on American technology companies. The demand, delivered in an interview rather than through any formal diplomatic channel, lands France's wine industry in familiar and uncomfortable territory.

"I asked him not to cha...