All five candidates landed punches during vigorous discussion on the big issues for France: jobs, terrorism, immigration, Europe.
But the faceoff between independent centrist Emmanuel Macron and far-right populist Marine Le Pen provided political theater, even moments of high drama in pitting two opposing visions of France.
Macron's performance, in particular, was being closely watched. One of the big surprises of the election has been the success of the former economics minister's new-look campaign, positioning himself as a centrist alternative to France's traditional left-right politics.
But Le Pen, the anti-immigration, anti-European Union leader of the National Front, was looking for opportunities to pounce. With polls suggesting that she and Macron could be direct rivals in the decisive May 7 runoff of the two-round election, both sought to score points against each other.
As Macron was discussing foreign policy, Le Pen portrayed him as wishy-washy, muttering: "It's empty, completely empty."
"We don't know what you want," she said.
Macron proved during the three-hour evening debate that overran and spilled past midnight that he can defend himself. With limited experience of public office, he sought to portray himself as presidential and hard to push around.
Some of the most heated exchanges centered on the place of religion in France and the separation of church and state.
Macron reacted vigorously when Le Pen accused him of being in favor of Muslim swimwear - essentially suggesting that her rival isn't really committed to France's secular values and policies.
"I don't need a ventriloquist," he retorted. "When I have something to say, I say it clearly."
He, in turn, accused Le Pen of using Islam to divide the French. Le Pen wants all visible religious symbols worn by people, including Muslim headscarves and Jewish kippahs, banned from public.
"The trap you are falling into, Madame Le Pen, with your provocations is to divide society," Macron said.
Macron also used humor to defuse Le Pen's attacks. After a thinly veiled dig from Le Pen suggesting that the former banker would be beholden to financial lobbies if elected, Macron told her: "You'd be bored without me."
While they were feisty, conservative candidate Francois Fillon was noticeably and unusually restrained. Once considered a leading contender to move into the presidency's Elysee Palace, Fillon's campaign has been badly hurt by accusations that his wife and children were paid with public money for jobs they allegedly did not do, which he denies. The ex-prime minister appeared weary and at times absent during the debate.
"I may have made mistakes. I have defects. Who doesn't? But I have experience," Fillon said.
Socialist candidate Benoit Hamon and far-left leader Jean-Luc Melenchon, both looking to boost their poll numbers, were the first to take swipes at Le Pen.
Hamon described Le Pen's attitude as "sickening" after she spoke of French schools as "a daily nightmare," so dangerous that pupils attend with "fear in their stomachs."
Melenchon interrupted Le Pen as she was calling for boosted French-language teaching.
"How do you learn French, dear madam? By speaking it!" he said.
Of the 11 candidates in the election, only the five who are expected to be the largest vote-getters in the first round were included in the debate.
The first-round vote is set for April 23; the top two candidates go to the May 7 runoff.
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