Wildly unpopular -> At 47% (or at least 46%)
Not exactly a huge margin to make up with a debate against a weak performer forthcoming.
French presidential elections are like US presidential elections - the loser is always guaranteed an absolute minimum 45/46 percent of the vote. In 2008 despite being from the same party as Bush being the most hated President in American history and despite a Vice-Presidential running mate like Sarah Palin who was an object of ridicule and complete crackpot - McCain still got 46% of the vote.
By French standards, if Sarkozy loses 54-46% it will be regarded as a landslide
You might want to read up on the 2002 French presidential election.
2002 seems to be the exception, not the rule.
