Warren Buffett is playing well in France.

A group of 16 of the richest people in France has signed a petition asking the French government to increase their taxes. The group includes Liliane Bettencourt, the billionaire heiress of LOreal; Christophe de Margerie, the head of oil giant Total; Frederic Oudea of bank Société Générale; and Jean-Cyril Spinetta, president of Air France KLM SA. (Given SocGen's share price, Mr. Oudea may not have as much wealth to tax).

The...