So, essentially, the French are cool with whatever public officials want to do sexually -- affairs or otherwise -- because they don't really have a choice, since their media are prohibited from reporting such things. If they eventually do find out about such an incident, there won't be any fallout from it unless the misbehavior was accompanied by gross incompetence and not just a lack of productivity.
And here's where the Petraeus affair becomes a very interesting case for the French. Chatter is divided between those who feel Petraeus should be able to sleep with whomever he wants because he has demonstrated competence in his job, and those who believe the case demonstrates incompetence on Petraeus' part by potentially compromising national security.
While French presidents such as Mitterrand, Jacques Chirac and others have had affairs, their side pieces were compartmentalized well away from matters requiring security clearances. Clearly, your love life has spiraled out of control when you're the CIA director and things have gotten to the point where Mistress No. 1 -- when she isn't giving speeches that may or may not include items from your pillow talk, like the possible existence of a secret CIA prison in Benghazi -- is harassing Potential Mistress No. 2 to the point that Potential Mistress No. 2 asks the FBI to get involved.
When your wife throws a lamp at your head, it's your own personal business. But when the FBI has to step in to untangle your "Love Pentagon" and offers you a sword on which to fall, and you can't imagine anything short of swan-diving on it, then things have reached the point of no return. The French book tour awaits, Mon Général!