PARIS -- Since at least the 19th century, the French have heard much talk about their decline. Of course, the French have never believed it. "Pas du tout! (Not at all!)" they might exclaim with a trademark shrug of the shoulders. But these days, judging by several best-selling books in France and the tone of a self-effacing discourse on national radio and television and in newspapers, the country has begun to again broach the subject of its own decline. The discussion touches on the loss of influence in the spheres of politics, economics, art, film, diplomacy, and even language. Even...