FRAGILE GLORY: A Portrait of France and the French by Richard Bernstein (Alfred Knopf: $24.95; 349 pp.) . It's easy to see what former New York Times Paris correspondent Richard Bernstein is getting at in the title of this book--that the splendors of French culture are rooted in a fading past. But Bernstein's lively, discursive sketch gives the lie to the word "fragile," for the people he writes about are robust and opinionated, and the places he visits steeped in tradition. Like many writers before him, Bernstein bravely struggles to define what makes the French special. Readers are likely to conclude--as the author does not, at least explicitly--that it lies in their deep-seated sense of superiority. Expecting the world to look its way for guidance, France, even today, sets standards in many fields that more powerful nations cannot match.