NANTES, France — The parliamentary candidates running under the banner of the newly elected president, Emmanuel Macron, appear poised to win a crushing electoral majority on Sunday that extends from France’s Alpine heights to the Brittany coast and from the Mediterranean to Paris.
Yet his party’s likely sweep of the legislative elections may disguise real challenges for Mr. Macron as well as for France, as the country tentatively journeys up a path of change it has long avoided.
Given the high abstention rate in the first round of voting last Sunday, just over 15 percent of all voters actually backed Mr. Macron’s parliamentary candidates. Yet his party could ultimately win as many as 80 percent of the seats in the 577-member National Assembly.
That disparity — between his potential to push through an agenda for deep change because of his majority and the narrowness of his true popular support — could eventually spell trouble for a young and relatively untested president. Given that, Mr. Macron may have but a fleeting window to persuade the French to stick with him. The expectations are high.
In about two dozen interviews in and around Nantes, a flourishing city near the Atlantic coast, voters expressed a mixture of wariness and romanticism about their new president, who is just 39 and had never before held elective office.
In Thouaré-Sur-Loire, a small suburb, Bernard Brevet, 68, a retired cleaning man, was typical of voters who seemed prepared to give Mr. Macron a chance, but on the condition that he quickly prove effective.
“He’s young, he has the future ahead of him, we have to give him at least a year,” Mr. Brevet said as he ordered meat at a butcher’s stand in an outdoor market. “He must bring reforms.”
While Mr. Macron may not generate broad enthusiasm, neither are people voting against him. It is in effect a hands-off stance by an electorate that seems prepared to let Mr. Macron advance by default. Changing that support from passive to active will be one of his biggest challenges.
For the time being, Mr. Macron is benefiting from a kind of honeymoon period. Many French are basking in the new sense of optimism he has ushered in, and a latent desire for their country to get unstuck, after years of relative economic and political malaise. Enough people are sufficiently discouraged by the status quo that they are willing to try something new.
“There is a sort of change in the culture,” said Marc Abélès, a professor of political anthropology at the academic institution École Des Hautes Études en Sciences Sociales.
“There was an atmosphere that was a bit deadening, the impression that one couldn’t get out, that one was cornered,” he said. “And I think against that backdrop something was pushed. We were completely looking at things negatively, and now people have a tendency to see things more positively.”
But others say that once the impact of Mr. Macron’s changes is understood, at least some segments of the population may actively resist him. That presents a lurking danger to his ability to succeed, said Jean Garrigues, a historian at the University of Orleans. Because those opposed to him lack much representation in Parliament, they may take to the streets, he said.
Nonetheless, there is a sense that Mr. Macron brings a breath of fresh air.
“He’s completely upended the landscape, and the thing one admires in him is his guts,” said Maurice Billet, a retired executive, as he purchased the first of the summer peaches at the Thouaré-Sur-Loire market. “The people are tired of half solutions.”
Noura Moreau, 45, who runs a restaurant and also serves as an assistant mayor in a neighboring town, was enthusiastic enough to join the campaign of the local République en Marche candidate, Sarah El Haïry, 28.
For Ms. Moreau, Mr. Macron is something of a hero-rebel willing to take on the establishment — although Mr. Macron, a former investment banker, is also a part of it.
“Emmanuel Macron has burned all the old codes,” she said, handing out campaign leaflets at the local market. “With him, there is going to be more dynamism. He’s younger, he’s going to make the country move.”
Candidates who, like Ms. Haïry, are political unknowns running under Mr. Macron’s umbrella, have been able to take advantage of his glow. If she were not running as a member of his coalition, she said, she might get 1 percent of the vote.
Ms. Haïry is in many ways representative of the candidates chosen by République En Marche and its ally the Democratic Movement — she comes from the Democratic Movement wing.
She is also an example of the parties’ strength and weaknesses. She has only ever run for political office before in internal party elections. She works as a negotiator — a mediator between unions and businesses when they discuss nonsalary-related aspects of remuneration, such as lunch hours.
Ms. Haïry is the daughter of a French-Moroccan anesthesiologist who moved to France when he was still in medical school and a mother who worked in business and has also been involved in charitable projects.
Ms. Haïry is from a family of high achievers. She has taken on the project of getting elected with enormous energy, relying on a campaign network largely set up with help from the République en Marche headquarters of about 36 people scattered in the many little communities in her district. Although she is Muslim by background, like Mr. Macron she believes in secularism in public life and does not wear a hijab, though she would not support a ban on it for adults.
A recent study of candidates for the Macron coalition found a plethora of people a lot like Ms. Hairy.
They “represent the upper-middle class, largely those with degrees, and the problem in France is that the popular classes, the workers, the blue-collar workers, they are not represented there,” said Luc Rouban, a researcher at the Center for the Study of French Political Life at Sciences Po in Paris.
“Yet the working class represent 40 percent of the French population,” he said.
The voters who turn out for Ms. Haïry, and those who sound open to voting for her, are in many respects a bit like the candidate: driven, optimistic and high achieving, although some are far older than she is.
Among those she was trying to convince last week was Céline Davy, 44, who runs a hair salon on the main street of the small town of Nort-sur-Erdre, which is part of her district.
With a shock of red-pink hair, Ms. Davy rushed around her salon on a recent day, periodically stopping to give a short lecture to Ms. Haïry about the difficulties of being a small-business woman.
The main problem, she said, is the social charges, meaning the taxes on top of the salary that employers must pay to ensure employees are covered for health care, retirement and unemployment insurance.
It makes it very expensive even to hire short-term employees, and almost every small-business owner in France is apt to lament those costs. Reducing that burden is a test that could make or break Mr. Macron and his Parliament in the months ahead.
“The businesses with fewer than 10 employees are the lifeblood of France, but I have the impression of working to pay social taxes,” Ms. Davy said. “I want to work well, but not to pay everything to the state.”