It's been quite a dramatic fall, and there's no sign that it's stopping. Hollande's presidency is now disapproved by 73% of voters. 94% of UMP voters disapprove, perhaps not surprising, but so do 80% of "workers" and 70% of Greens.
The odd thing is that this massive disapproval does not seem to be associated with the kind of widespread fulmination, loathing, and mockery that accompanied Sarkozy's fall from grace. The French don't hate Hollande; they just don't think he's up to the job. This judgment is no doubt unfair. The job that citizens want the president to accomplish is clearly impossible. But one can imagine another president doing a better job of explaining things, clarifying his choices, mapping out future directions, accounting for past misperceptions and failures. Something isn't clicking between Hollande and his public. The rise of the Front National, apparently confirmed by the voting in Villeneuve-sur-Lot, is just one symptom of a wider malaise.
The danger is that Hollande now has no cushion. If he does finally act forcefully, as he has threatened to do in regard to pension reform, he will provoke opposition. His prime minister is such a pallid figure that he provides no protection for the president. All anger will be directed at him, and he has no way to deflect it.