The tone was ill-tempered from the get-go, with no common ground or love lost between the two candidates

The only face-to-face televised debate between France’s presidential candidates turned into an uncivil, no-holds-barred head-on clash of styles, politics and personalities on Wednesday.

Emmanuel Macron called his far-right opponent Marine Le Pen a “parasite” who would lead the country into civil war. She painted the former banker as a lackey of big business who is soft on Islamic extremism.

Neither landed a knockout blow in the 2-hour prime-time slugfest but not for lack of trying. The tone was ill-tempered from the get-go, with no common ground or love lost between the two candidates and their polar opposite plans and visions for France. Both sought to destabilize each other and neither really succeeded.

For the large cohort of voters who remain undecided, the debate at least had the merit of making abundantly clear the stark choice facing them at the ballot box on Sunday.

Neither candidate announced major shifts in their policy platforms. They instead spent much of their carefully monitored allotments of time attacking each other often personally.

Ms. Le Pen’s choicest barb came as she argued that Mr. Macron, if elected, would be in the pocket of German Chancellor Angela Merkel. “Either way France will be led by a woman; either me or Madame Merkel,” she said derisively.

Macron gave as good as he got and, at times, got the upper hand with his pithy slights. In the closing minutes, he used a sharp-tongued monologue to target one of Le Pen’s biggest vulnerabilities- her father, Jean-Marie Le Pen, the extreme-right former presidential candidate repeatedly convicted for hate speech and who founded her party, the National Front.

Throughout, Mr. Macron portrayed Ms. Le Pen as an empty shell, shaky on details and facts, seeking to profit politically by stirring up hatred and the anger of French voters a dominant theme of the campaign without feasible proposals. He called her “the high priestess of fear.”

“Your project consists of telling the French people, ‘This person is horrible.’ It’s to cast dirt. It’s to lead a campaign of lies and falsifications. Your project lives off fear and lies. That’s what sustains you. That’s what sustained your father for decades. That’s what nourished the extreme right and that is what created you,” Macron said. “You are its parasite.”

“What class!” Mr. Le Pen retorted.

One of the most heated exchanges was on terrorism a top concern for Le Pen’s voters and many French in the wake of repeated attacks since 2015. Saying that Islamic extremists must be “eradicated,” Le Pen said Macron wouldn’t be up to the task.

“You won’t do that,” she charged.

Saying France’s fight against terror would be his priority if elected, Mr. Macron countered that Ms. Le Pen’s anti-terror plans would play into extremists’ hands and divide France.

“The trap they’re setting for us, the one that you’re proposing, is civil war. What the terrorists expect is division among ourselves. What the terrorists expect is heinous speech,” Mr. Macron said.

Sitting opposite one another at a round table, the debate quickly became a shouting match. She had piles of notes in colored folders, and referred to them occasionally. His side of the table was sparser, with just a few sheets of paper. He at times rested his chin on his hands as she spoke, fixing her in his gaze and smiling wryly at her barbs.

They clashed over France’s finances, its future and their respective proposals for tackling its ills. He scoffed at her monetary plans, saying reintroducing a franc for purchases within France but allowing big firms to continue using the shared euro currency that Le Pen wants to abandon made no sense.

She dismissed his economic proposals with sweeping critiques and bristled at his suggestions that she didn’t understand how finance and business work.

“You’re trying to play with me like a professor with a pupil,” she said.

They also clashed over foreign policy. Macron said he wants to work with U.S. President Donald Trump on intelligence-sharing, at the United Nations and on climate change. He spoke less favorably of Russian President Vladimir Putin, saying on many subjects “we don’t have the same values and priorities.”

“We have no reason to be in a cold war with Russia,”Ms. Le Pen said.

While Mr. Macron was borderline patronizing at times, she sought but failed to make it seem like he has trouble controlling his temper, which stayed fairly even throughout.

“You’re interrupting me about every 10 seconds. I sense you’re a bit exasperated,” she said.

The debate offered risk and reward for both. A major trip-up or meltdown beamed direct into the homes of millions of electors could have dented their presidential ambitions in the closing stages of the intense campaign that has already steered France into uncharted territory. The first round of voting on April 23 eliminated mainstream parties from the left and right and propelled the 39-year-old Macron, who has no major party backing, and the 48-year-old Le Pen into the winner-takes-all runoff on Sunday.

Trailing in polls, Ms. Le Pen needed but failed to land a knockout blow in the debate to erode the seemingly comfortable lead of Mr. Macron, the front-runner who topped round one, nearly three points ahead of Ms. Le Pen.

For Mr. Macron, the priority was to prevent Le Pen from making up ground in the race’s final days. Mission accomplished.