An opinion poll carried out by the Ifop polling company showed Hollande's ratings jump by a massive 21 percentage points to 40 per cent after the spate of attacks two weeks ago that left 17 people dead.
"This is a rare phenomenon in the history of opinion polls," in France, said Ifop expert Frederic Dabi.
He said the only other such example was when Francois Mitterrand soared 19 points in the ratings during France's participation in the Gulf War of 1990-1991.
Prior to the attacks, record French unemployment, sluggish growth and a string of personal and political scandals had sent Hollande's ratings plunging to historic lows.
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But his response to the country's worst attacks in decades has seen his image transform from that of bumbling, dithering president to solid, reassuring statesman.
Not known for his charisma, Hollande moved the nation with several powerful speeches calling for unity in the face of the attacks on Charlie Hebdo satirical magazine, a Jewish supermarket and police officers.
But Andrew Knapp, an expert in French politics at Britain's University of Reading, said the afterglow was unlikely to last for Hollande, "unless there is better news on another front".
He said if the situation remained calm in France, people would quickly "get back to the old tedious business of economic growth and unemployment and Hollande's ratings will slide down accordingly".
Conversely, fresh attacks could also hurt him as the feeling would likely set in that whatever remedy Hollande had applied was not working, he argued.
But, Guenole said, whatever happens, the days of Hollande-bashing were probably over, as he had finally proven himself a capable leader.