We have several hypotheses to explain the more muted French response.

Image Credit... Ed Alcock for The New York Times

First, Mr. Piketty has been on the intellectual scene, and the darling of the French Socialist party and intellectuals, for some time already. An early appointment as an economic adviser to Ségolène Royale, the Socialist presidential candidate in 2007, gave him a platform to present his ideas to the news media. He also has had access to President François Hollande and many other leaders for a while, so Mr. Piketty is older news to the French political elite and journalists alike.

Besides, in France, unlike in the United States, most people take for granted the notion that income inequality is growing and destructive. A book that tells people what they already believe may receive approval without generating adulation.

Additionally, the book’s timing may be behind the state of French debate. Had it been released in the halcyon days of Mr. Hollande’s 2011 presidential campaign, when many French considered soak-the-rich talk and 75 percent marginal tax rates to be practical fiscal strategies, Mr. Piketty’s book might have made a bigger splash in France. Today, with the economy still struggling, Mr. Hollande is talking about tax cuts rather tax increases. The 75 percent rate has suffered constitutional challenges, and even celebrity backlashes, such as when Gérard Depardieu pursued and received Russian citizenship to lower his tax rate. Mr. Hollande seems to be steering France away from its traditional role as a defender of high taxes and toward some structural reforms, albeit at a slow pace. During his New Year address, Hollande even turned into a rhetorical supply-sider, making the case for cutting taxes and public spending, improving competitiveness, and creating a more investor-friendly climate. In any case, the French appetite for stiff tax increases has diminished. As Guy Sorman recently explained in his review of the book, Mr. Piketty’s policy prescription of “more social state” and “more taxes” is possibly heard by French ears as “the more things change, the more they stay the same.”

Finally, some other French economists have taken the lead in challenging Mr. Piketty’s empirical claims. One recent paper by four economists at l’Institut d’Etudes Politiques de Paris challenges Mr. Piketty’s view that inequality has increased because the return to capital has been greater than general growth in the economy. The current shorthand is “r > g.”

The paper argues that the higher growth of capital rests entirely on returns to housing, and takes technical issues with the book’s treatment of housing, too. If Mr. Piketty’s argument depends on housing, it hardly seems to match his basic story about the ongoing ascendancy of capitalists.