A president should of course ignore his or her approval rating. The public is fickle, and short-term thinking is a sure recipe for failure. But France2 reported last night that Hollande's approval had fallen 11 points in the month of August, from 54% positive to 43%. His fall from his post-election high of 67% positive is the fastest on record. Sarkozy at this point in his presidency was still above 50, and he did not drop to 43 until after the "casse-toi pauvre con" incident, almost 9 months into his term (after which, to be sure, he never recovered).
Clearly, "normality" is not enough, and not being Sarkozy is not enough. There is a danger to winning an election because the electorate is disenchanted with the incumbent, as first Obama and now Hollande have discovered. There is an expectation of improvement that comes simply from the fact that the thorn has been removed. But when the thorn has caused an infection, positive action needs to be taken, and if it isn't, the hurt only grows worse, and is magnified by disappointment.