A workmen’s café in central France was overwhelmed with phone calls from gourmet diners wanting to book tables after it was awarded a Michelin star — by mistake, it later turned out. Reporters, TV crews and prospective customers were astounded when they turned up at the Bouche à Oreille, in the small town of Bourges, to find a cheap and cheerful eatery with red and white polka dot plastic tablecloths. Many patrons wear high-visibility vests, it is often packed at lunchtime and the atmosphere is lively, with customers ordering beers at the bar. It serves its regular clientèle of local...