In the first round of the presidential election on April 23, voters in many poorer Parisian suburbs did turn out, but for the fiery candidate on the extreme left, Jean-Luc Mélenchon, who channeled the anger of communities neglected by the political system. And many also chose not to vote. That second option — not voting — is now a real possibility in the final round for those who previously voted for Mr. Mélenchon, even though they arguably have the most at stake.
Just how many voters abstain could determine whether Ms. Le Pen can upend expectations and beat Mr. Macron. The prevailing assumption is that a broad majority of voters — a so-called Republican Front that includes the poorer suburbs — will come together behind Mr. Macron in the name of turning back Ms. Le Pen and the far right. But a low turnout could threaten this belief and help Ms. Le Pen.
In France’s poor suburbs, many French are of Arab extraction with parents or grandparents who came from Algeria, Morocco or Tunisia. Many are also from sub-Saharan Africa; the former French colonies of Ivory Coast, Mali, Senegal and Togo; and what was once French Indochina, today’s Cambodia, Laos and Vietnam. For them, neither the right nor the left has delivered when it comes to making jobs more available and reducing discrimination.
Recent terrorist attacks have worsened the stigma attached to immigrants and Muslims. A number of the house searches after the terror attacks in and around Paris on Nov. 13, 2015, were conducted by police in Seine-St.-Denis, the political jurisdiction that includes Stains.
“The second round is a catastrophe,” said Cheker Messaoudi, 29, a Frenchman of Tunisian heritage. “I think with Macron we are facing a war on the economy and with Le Pen we are facing a civil war, so it is bad both ways.”
With an abstention rate of 38 percent including blank ballots in contrast to 23.5 percent nationwide in the first round of the presidential election, Stains reflects a particularly high degree of disillusionment. A community of about 38,000 inhabitants on the outskirts of Paris, it voted overwhelmingly for Mr. Mélenchon, a former Trotskyite, who finished fourth. With Mr. Mélenchon out, many people see the race, as expressed in an old French saying, as a choice between “la peste et le choléra” (the plague and the cholera).
To many people here, the policy proposals of both candidates are unattractive: Ms. Le Pen proposes a law-and-order program that would place binational Muslims at higher risk of expulsion from the country if they are considered even remotely connected to those suspected of having terrorist links. She also has inveighed against wearing a head scarf in public.
Mr. Macron, a former banker, is seen as close to the moneyed elite. He is disparaged for his support for Uber, which employs many people at low wages and often under poor conditions. He worked as a minister to the Socialist president François Hollande, who promised improvements that never arrived.
Sociologists and political scientists who study France’s poorer suburbs with substantial minority populations, known here as banlieues, said neither candidate had given people much reason to vote for him or her.
“They are really tired of people talking about the banlieues but not doing anything,” said Julien Talpin, a researcher in political science at the University of Lille. “Macron in the banlieues is a kind of big failure. He appears to be an embodiment of the establishment, of the elite, and people can tell he’s not one of them.”
Mr. Macron received 22 percent of the vote in Stains.
Thomas Kirszbaum, a sociologist, says the demographics and voting patterns of the poorer suburbs are far more complex than is widely understood. Living together are people of immigrant background, who vote on the far left or not at all, and some longtime residents, usually white, but also some immigrants, who vote on the extreme right. In Stains, nearly 15 percent of voters favored Ms. Le Pen.
Then there is a small, new class of young entrepreneurs, both Muslims and non-Muslims, many of whom support Mr. Macron, who has made outreach to entrepreneurs a priority.
Mr. Talpin noted a big change from 2012, when the poor suburbs turned out in large numbers to vote for the Socialist Party candidate, Mr. Hollande; he was running against President Nicolas Sarkozy, whom many people opposed.
“They haven’t really mobilized so much against Le Pen,” he said, despite the xenophobic tone of her campaign. “They are somehow feeling they are experiencing that discrimination on a daily basis.”
Sitting in his office not far from the central square in Stains, the mayor, Azzédine Taïbi, who is Muslim, suggested that it would take someone who inspired people, as well as effective government programs, to get people to embrace the political system again.
“This is an electorate that has nothing more to lose,” he said. “For this reason, what I see in this election is a sense of abandonment from working-class people: Either we leave them in total hopelessness or we build hope with them through an alternative policy.”
Yassine Belattar, a popular stand-up comedian who grew up in the suburbs, said that anti-government feeling was significantly stronger this year because of Mr. Mélenchon, who ratified people’s sense of injustice and their fury at the system.
“He manipulates anger for his personal ends,” said Mr. Belattar, referring to Mr. Mélenchon, adding that the candidate’s refusal to endorse Mr. Macron helps Ms. Le Pen. Mr. Mélenchon announced on Friday that he would not vote for Ms. Le Pen but refused to endorse Mr. Macron.
Mr. Belattar said he intended to vote for Mr. Macron.
Yet the sense of betrayal is acute among many people, not least toward the Socialists who had promised change but failed to follow through.
“Hollande visited the suburbs but these were visits for the media,” said Slimane Abderrahmane, an assistant mayor in Bobigny, a neighboring suburb to Stains, where the abstention rate in the vote last week was 37 percent (including blank ballots). Mr. Mélenchon took 43 percent of the vote.
“Hollande promised social and economic programs,” he added. “He promised to end racial profiling. He was full of promises that people never saw come true.”
Mr. Abderrahmane said he was voting for Mr. Macron only because he was afraid that the situation for Muslims would get markedly worse under Ms. Le Pen.
However, his friend Sylvain Legér, a municipal counselor who is white and has spent his whole life in Bobigny, said that after voting for Mr. Mélenchon in the first round, he could not bring himself to vote for Mr. Macron. He instead will abstain.
“He’s for globalization 100 percent,” Mr. Legér said. “What does that mean when workers come from their own country, mix with French workers, and on one side you have young people who want to work and on the other you have people who come from elsewhere in Europe or from other countries and who work for less?”
On Friday, Catharine Bonté, 75, a former nurse’s aide, recalled writing letters to past presidents seeking help.
“They all helped me a bit with social care,” said Ms. Bonté, who is black. “And Giscard d’Estaing’s wife even came to support me once because I was a single mother and I was a victim of injustices and racism.”
“But Hollande, he never helped me; he never answered my letters,” she added. “So I understand the ones who gave up on voting. There is a lot of suffering here.”
An earlier version of this article misspelled in some instances the surname of the far-left presidential candidate. As the article correctly notes elsewhere, he is Jean-Luc Mélenchon, not Mélanchon.