Let's go back in time for some context.
The French never understood why President Bill Clinton was impeached for the Monica Lewinsky scandal following disapproval by those "puritanical Americans." Sure, he may have lied about the dalliance under oath, but he was just lying about sex. In French culture, it shouldn't have been the voting public's business as long as he was still competently doing his job. (Not that we ever really know how much more competent a person might be in executing his duties in the absence of the extramarital sex; why is the assumption always that they were giving it their all?)
As disinterested as the French may seem about top-level politicians' sexual dalliances, they're ultimately far less accepting of the results. Former French President Francois Mitterrand managed to hide a second family from the public, even as taxpayer resources were being used to support them. The daughter born to Mitterrand and his mistress out of wedlock is now a 37-year-old author and university professor, Mazarine Pingeot, and she's still being confronted in the French media about having been secretly raised on taxpayer funds.
Similarly, the French were happy to ignore former International Monetary Fund chief Dominique Strauss-Kahn's extramarital sexual hyperactivity for years, until it became impossible to ignore. That happened when a Manhattan hotel maid's accusations caught the attention of legal authorities and the American press. Strauss-Kahn has since returned to opened floodgates in France and is currently facing "aggravated pimping" charges in Lille, in connection with a prostitution ring.
It's not as if the French typically have the option of paying attention to such things before they spin out of control. The French media is prohibited by law from publishing personal or private details about a public figure without the public figure's permission. Even when sex merges with a scandal that happens to be in the public interest, French jurisprudence mandates that anything belonging to the private realm must be carefully parsed out of all media coverage.