PARIS—Citing "outrageous" snack prices at the legendary Palais Garnier opera house, local resident Philippe Michaud discreetly smuggled a terrine of foie gras and half a pound of sautéed scallops into Monday evening's production of Strauss's Der Rosenkavalier. "That's how operas make all their money, by jacking up concessions prices," Michaud said. "Why should I shell out €175 for hors d'oeuvres at the concessions booth when I can just sneak some in underneath my cummerbund?" Sources said that Michaud also brought along a concealed bottle of 1986 Krug Clos du Mesnil, which he surreptitiously uncorked during the loudest point of Princess von Werdenberg's aria at the end of Act I.