PARIS — Some of Emmanuel Macron’s advisers acknowledge the upstart politician blundered on the night of his greatest triumph — and that misstep is prompting worries about the French presidential favorite's capacity to avoid other mines that may lay in wait.

While far-right leader Marine Le Pen's odds of victory are long nearly two weeks before the runoff, Macron faces multiple dangers, from soft turnout to another embarrassing gaffe, that could narrow his margin of victory and undermine his authority as president, even though an outright upset isn't yet feared.

Macron may be his own worst enemy, his team of aides and supporters feel. The independent centrist candidate, who came first in the presidential election's first round with 24 percent of the vote, celebrated in an exuberant fashion that would have been more appropriate if he’d actually been elected president. “The key word should have been sobriety, and we forgot that,” said an aide in his inner circle.

On Sunday night, Macron greeted passers-by and sang the Marseillaise from the roof of his campaign headquarters in the south of Paris, then went to a large venue nearby for a long, rambling and unfocused victory speech in front of ecstatic supporters. He ended the night by celebrating with aides and friends in a Montparnasse restaurant that his campaign had fully booked.

“The whole evening looked like he’d already won the presidency, which was a terrible message to send” — Macron adviser

A merry Macron emerged from the restaurant, La Rotonde, at 2 a.m. to deny that he’d behaved as Nicolas Sarkozy had on the night he was elected president in 2007. Sarkozy’s firmly established “bling bling” reputation came from the evening he spent at Le Fouquet’s, one of the most expensive Paris restaurants, along with rich show business and celebrity friends.

To emphasize the difference, one of Macron’s long-time allies, Gérard Collomb, the Socialist mayor of Lyon, went as far as publishing the La Rotonde menu, to prove it had little in common with Le Fouquet’s.

But to concerned Macron aides, the problem has nothing to do with the price of the steak tartare. “The whole evening looked like he’d already won the presidency, which was a terrible message to send,” the adviser said.

The celebration was doubly inappropriate, he added. “First because we haven’t won yet, second because you don’t rejoice on the night another Le Pen makes it to the second round.”

Marine Le Pen’s father, Jean-Marie, stunned political France in 2002 when he beat Socialist Party candidate Lionel Jospin to the second round, before losing to Jacques Chirac with only 18 percent of the vote.

“I find it indecent to party when Marine Le Pen is in the second round,” said Tourcoing mayor Gérald Darmanin, a conservative who now supports Macron. Darmanin went on to note that Chirac hadn’t celebrated his victory against Le Pen senior 15 years earlier.

Back on the trail

Macron has hit the campaign trail again, and aides insist he's not taking victory for granted. Nothing would be worse than behaving as if the presidency was a done deal. Polls predict he will beat Le Pen with 60 percent of the vote but that doesn’t mean he's home free.

Macron’s goal is clear: to convince a significant portion of voters who backed other candidates in the first round that they should come to the polls and not abstain. To do that, he will have to navigate several potential obstacles.

The first is another major gaffe that would irk either leftists who backed far-left leader Jean-Luc Mélenchon or Socialist Party candidate Benoît Hamon or conservatives, many of them practicing Catholics, who supported former Prime Minister François Fillon.

According to a Harris Interactive poll, 47 percent of Fillon voters, 52 percent of Mélenchon voters and 76 percent of those who went for Hamon say they will vote for Macron on May 7.

If they don’t change their minds, that's more than enough to guarantee Macron a comfortable victory. And even a larger-scale abstention on the part of those candidates’ voters doesn’t seem to move the needle much.

Another possible pitfall would be a Russian hack attack. Computer security firm Trend Micro confirmed that the Macron campaign’s emails had been the target of numerous attacks from the Russian hacker group known as Fancy Bear, but so far, according to Macron aides, to no avail.

More serious damage would come if hackers uncovered potential scandals, even as Macron aides confidently insist there are none to uncover. As for so-called “fake news,” the campaign has proven proactive at detecting and defusing damaging rumors — on Macron’s alleged wealth or his income tax returns, for example.

The parliamentary challenge

The real worry among senior aides is not the risk of defeat on May 7, but that of an unconvincing victory.

“If Macron can’t navigate the minefield properly, he will lose ground. And the beginnings of his presidency will be seen as problematic, which could hurt us in the crucial parliamentary election in June,” said another Macron aide.

Macron’s victory against Le Pen will be judged in light of those polls that see him winning with 60 percent of the vote, and also could be compared with Chirac’s 82 percent win against her father in 2002. “If we get, say, below the 55 percent threshold, we’re in trouble,” the aide added.

“He has succeeded so far on an unexpected scale, so how can you tell him he should change?" — A Macron aide

A weak victory would cost Macron momentum and impair his ability to lead his En Marche movement in the two-round parliamentary election on June 11 and 18. It would shake his conservative opponents out of their current stupor, and energize them in the intervening weeks.

Macron, aides said, is a quick learner and has already understood that he made a faux pas on election night. But that blunder shows the fragility of a campaign entirely built around the candidate and his political instincts.

“He has succeeded so far on an unexpected scale, so how can you tell him he should change? But on some days you feel the lack of serious adult political strategists around him,” said the aide.

“Not the type who tell him when he’s made a mistake, but the type who warn him when he’s about to make one,” he added.