By Emma-Jane Kirby
BBC News, Metz, eastern France
Nicolas Sarkozy has been the front runner in every French election poll since Christmas, but over the past few days he has faced an onslaught of criticism about his personality and has had to answer about whether he has the right temperament to govern France.
Sarkozy has been accused of alienating some voters
The Socialist candidate Segolene Royal accused her conservative counterpart of being the "candidate for brutality", while the former equal opportunities minister, Azouz Begag, claimed Mr Sarkozy had once threatened to punch his lights out.
Mr Sarkozy was obliged to defend his reputation on prime time French television, acknowledging that he did frighten some people but reassuring voters that the same had once been said of President Mitterrand and President Chirac.
Spending a day with him on the campaign trail in Metz, I quickly understood that the former interior minister is buzzing with nervous energy.
I watched him address a group of former miners at a closed mine - as he told them that France needed to work harder, the veins on his temples bulged and he jabbed his finger at them like a strict school teacher.
It is this didactic rhetoric which alienates many people but his former campaign adviser, Frank Tapiro, defends his old friend.
"When you want to change the rules you've got to be very powerful. You have sometimes to say it a little louder but that doesn't mean it's an order. Nicolas Sarkozy is a bit like the advertising campaign for Marmite in the UK - you either love it or hate it."
As interior minister, Mr Sarkozy earned himself a reputation as a tough hardliner determined to crack down on crime.
Mr Sarkozy's "work harder" message angers some
Many young people felt alienated by his forcefulness and Alexandre Lazerges, a writer with the youth magazine Technikart, says it has cost him the youth vote.
"Think of it in terms of a family. Segolene Royal - she's like your annoying mother, telling you to clean your room but at least she'd give you some pocket money so you could go out on a Saturday night.
"But Sarkozy is obviously the strict father who may want what's best for you but is not able to explain it to you so you would always want to go against him. It's like the army. Don't think, just obey."
Oozing charm on a tour of a heating factory in Metz, Mr Sarkozy reduced the female factory workers to a blushing, giggling heap as he kissed them, flattered them and posed for photographs with them.
Clearly, he is trying hard to win back hearts and to soften his image, but he won't compromise his central message.
The major theme of his rally speech that night was authority - how France has lost its respect for it and how he would make restoring authority his number one issue.
Many French voters are yet to make up their mind
He lamented the fact that children no longer respected their parents and that students did not obey their teachers. "We thought the revolution of 1968 liberated us," he bellowed. "It didn't, it brought us into moral decline."
Mr Tapiro promises that underneath this brash and hard exterior lies a sensitive little soul. "The status of president will change him and will help him show his real personality.
"Many things will be corrected so that French people who didn't like him and who were maybe a little frightened of him will discover the real Nicolas Sarkozy. And I can tell you that he's a human guy, a kind guy, a generous guy."
Lifted off my feet in the media scrum, I suddenly find myself shoulder to shoulder with Mr Sarkozy. "Are you going to win?" I ask him. "I don't know," he shrugs. "That's up to the French people."
The problem is with only four days to go before the vote, many French people still have not worked out quite who Nicolas Sarkozy really is.