— Emmanuelle Lellig was having none of it.

The candidates in France’s presidential election, she sneered, spend their time hurling insults at one another and throwing out promises that they have no intention of keeping.

“How can we believe them?” she asked between sips of morning coffee at an outdoor cafe this week. “They’re not going to do what they say, anyway. For me, the campaign goes in one ear and out the other.”

Lellig, a 24-year-old intern at a public relations agency in this graceful old city 150 miles southwest of Paris, has not made up her mind whether to vote Sunday in the first round of France’s election, much less in the second round May 6. Even if she votes, she said, she has not decided whether to back President Nicolas Sarkozy, main rival Francois Hollande of the Socialist Party or one of the eight minor candidates spread from the far right to the far left.

Lellig, in short, is emblematic of the joker that could produce surprises in France’s presidential race. Despite opinion polls that for months have put Sarkozy and Hollande neck and neck in the first round and given Hollande a decisive edge in the runoff, a number of polls have predicted that nearly one-third of France’s 43.2 million registered voters will make up their minds on whether to vote at the last minute or will not decide on a candidate until the day they cast their ballots.

This marks a shift from past French elections, in which voter sentiment largely crystallized before the final week of campaigning, polling experts explained. The participation rate is likely to be around 75 percent, they estimated. By U.S. standards, that would be a massive turnout. But by French standards it marks a continuing decline and, they emphasized, could leave the country with a bloc of voters whose preferences are hard to predict.

Jacques Le Goff, a law professor at the University of Nantes, lamented the trend in a front-page editorial Thursday in the main regional newspaper, Ouest-France. “How can it be that this act that is such a strong symbol, a manifestation of popular sovereignty and an incarnation of citizenship, ends up so pale and faded?” he asked.

Many of those who abstain or cannot make up their minds are young people who have not yet fully integrated into society’s civic responsibilities. But many are also older adults who have grown disgusted with a political system they see as remote and unresponsive to the people. This is particularly true in distant suburbs and provincial cities, where the political fervor of Paris seems like frivolity from another world.

“Nobody believes in it any more,” said Eric Fairnand, 38, the owner of a chic brasserie strategically located just in front of St. Peter’s Cathedral, the main Nantes church. “The candidates make all kinds of promises that they never keep. Whether they are on the left or the right, they treat us like we are sheep, like we are stupid jerks.”

In that vein, the leftist news magazine Marianne headlined this week’s issue, over photos of the five most popular presidential candidates: “The biggest lies of the campaign. Who lies the most? Who lies the best?”

Fairnand, who owns other businesses in this port city of 600,000 residents, said he voted for the conservative Sarkozy in 2007 and probably will do so again, chiefly because he fears a victory by Hollande would mean higher taxes for entrepreneurs. But he expressed dismay at Sarkozy’s record over his five-year term and said that Sarkozy was making campaign gestures, such as rescuing factories threatened with bankruptcy, that he should have been working on long ago.

“Now he does it?” Fairnand jeered. “He could have started five years ago.”

Some abstentions, analysts pointed out, could be blamed on the coincidence of having Sunday’s first-round voting at the tail end of Easter vacations, when large numbers of families are still in the Alps for end-of-season skiing. Beyond that, experts have tried to determine what has been triggering voters’ doubts and hesitations but have not come to widely accepted conclusions.

Some point to a 24-hour news cycle on France’s relatively recent all-news television channels. The pressure to create several headlines a day to grab jaded viewers’ attention, they said, prevents candidates from focusing on a single issue long enough to explain their proposals. Others cite the number of candidates — 10 — and laws requiring that each get an equal amount of television and radio time, including one who proposes that France should colonize the moon.

As a result of both factors, polling experts complained, the campaign often appears to many people, particularly outside Paris, like a confetti storm of declarations and denunciations unconnected to their daily lives.

Sarkozy, in an interview Friday in Le Figaro newspaper, promised that this will be the last presidential election with equal-time rules, no matter who comes out the victor. “All this leads to a caricature of democracy,” he said. “We are in a formal equality that is not a real equality.”

Hollande, also eager to counter the trend, emphasized in a recent interview that he has promised nothing that he cannot carry out if he is elected.

But Pierre Ndiaye, a 19-year-old communications student at the University of Nantes, said he plans to stay away from the polling booths — and urges others to do the same — because the French political system does not work. Candidates such as Hollande can make all kinds of promises during the campaign, he said, but there is no system for making them adhere to what they pledged once they become president or members of parliament for five-year terms.

“It’s cynical,” he declared.