PARIS — The threat is said to be existential. It fuels secessionism. Gnaws at national unity. Abets Islamism. Attacks France’s intellectual and cultural heritage.

The threat? “Certain social science theories entirely imported from the United States,’’ said President Emmanuel Macron.

French politicians, high-profile intellectuals and journalists are warning that progressive American ideas — specifically on race, gender, post-colonialism — are undermining their society. “There’s a battle to wage against an intellectual matrix from American universities,’’ warned Mr. Macron’s education minister.

Emboldened by these comments, prominent intellectuals have banded together against what they regard as contamination by the out-of-control woke leftism of American campuses and its attendant cancel culture.

Pitted against them is a younger, more diverse guard that considers these theories as tools to understanding the willful blind spots of an increasingly diverse nation that still recoils at the mention of race, has yet to come to terms with its colonial past and often waves away the concerns of minorities as identity politics.

Disputes that would have otherwise attracted little attention are now blown up in the news and social media. The new director of the Paris Opera, who said on Monday he wants to diversify its staff and ban blackface, has been attacked by the far-right leader, Marine Le Pen, but also in Le Monde because, though German, he had worked in Toronto and had “soaked up American culture for 10 years.”

The publication this month of a book critical of racial studies by two veteran social scientists, Stéphane Beaud and Gérard Noiriel, fueled criticism from younger scholars — and has received extensive news coverage. Mr. Noiriel has said that race had become a “bulldozer’’ crushing other subjects, adding, in an email, that its academic research in France was questionable because race is not recognized by the government and merely “subjective data.’’

The fierce French debate over a handful of academic disciplines on U.S. campuses may surprise those who have witnessed the gradual decline of American influence in many corners of the world. In some ways, it is a proxy fight over some of the most combustible issues in French society, including national identity and the sharing of power. In a nation where intellectuals still hold sway, the stakes are high.

With its echoes of the American culture wars, the battle began inside French universities but is being played out increasingly in the media. Politicians have been weighing in more and more, especially following a turbulent year during which a series of events called into question tenets of French society.

Mass protests in France against police violence, inspired by the killing of George Floyd, challenged the official dismissal of race and systemic racism. A #MeToo generation of feminists confronted both male power and older feminists. A widespread crackdown following a series of Islamist attacks raised questions about France’s model of secularism and the integration of immigrants from its former colonies.

Some saw the reach of American identity politics and social science theories. Some center-right lawmakers pressed for a parliamentary investigation into “ideological excesses’’ at universities and singled out “guilty’’ scholars on Twitter.

Mr. Macron — who had shown little interest in these matters in the past but has been courting the right ahead of elections next year — jumped in last June, when he blamed universities for encouraging the “ethnicization of the social question’’ — amounting to “breaking the republic in two.’’

“I was pleasantly astonished,’’ said Nathalie Heinich, a sociologist who last month helped create an organization against “decolonialism and identity politics.’’ Made up of established figures, many retired, the group has issued warnings about American-inspired social theories in major publications like Le Point and Le Figaro.

For Ms. Heinich, last year’s developments came on top of activism that brought foreign disputes over cultural appropriation and blackface to French universities. At the Sorbonne, activists prevented the staging of a play by Aeschylus to protest the wearing of masks and dark makeup by white actors; elsewhere, some well-known speakers were disinvited following student pressure.

“It was a series of incidents that was extremely traumatic to our community and that all fell under what is called cancel culture,’’ Ms. Heinich said.

To others, the lashing out at perceived American influence revealed something else: a French establishment incapable of confronting a world in flux, especially at a time when the government’s mishandling of the coronavirus pandemic has deepened the sense of ineluctable decline of a once-great power.

“It’s the sign of a small, frightened republic, declining, provincializing, but which in the past and to this day believes in its universal mission and which thus seeks those responsible for its decline,’’ said François Cusset, an expert on American civilization at Paris Nanterre University.

France has long laid claim to a national identity, based on a common culture, fundamental rights and core values like equality and liberty, rejecting diversity and multiculturalism. The French often see the United States as a fractious society at war with itself.

But far from being American, many of the leading thinkers behind theories on gender, race, post-colonialism and queer theory came from France — as well as the rest of Europe, South America, Africa and India, said Anne Garréta, a French writer who teaches literature at universities in France and at Duke.

“It’s an entire global world of ideas that circulates,’’ she said. “It just happens that campuses that are the most cosmopolitan and most globalized at this point in history are the American ones. ’’

The French state does not compile racial statistics, which is illegal, describing it as part of its commitment to universalism and treating all citizens equally under the law. To many scholars on race, however, the reluctance is part of a long history of denying racism in France and the country’s slave-trading and colonial past.

“What’s more French than the racial question in a country that was built around those questions?’’ said Mame-Fatou Niang, who divides her time between France and the United States, where she teaches French studies at Carnegie Mellon University.

Ms. Niang has led a campaign to remove a fresco at France’s National Assembly, which shows two Black figures with fat red lips and bulging eyes. Her public views on race have made her a frequent target on social media, including of one of the lawmakers who pressed for an investigation into “ideological excesses’’ at universities.

Pap Ndiaye, a historian who led efforts to establish Black studies in France, said it was no coincidence that the current wave of anti-American rhetoric began growing just as the first protests against racism and police violence took place last June.

“There was the idea that we’re talking too much about racial questions in France,’’ he said. “That’s enough.’’

Three Islamist attacks last fall served as a reminder that terrorism remains a threat in France. They also focused attention on another hot-button field of research: Islamophobia, which examines how hostility toward Islam in France, rooted in its colonial experience in the Muslim world, continues to shape the lives of French Muslims.

Abdellali Hajjat, an expert on Islamophobia, said that it became increasingly difficult to focus on his subject after 2015, when devastating terror attacks hit Paris. Government funding for research dried up. Researchers on the subject were accused of being apologists for Islamists and even terrorists.

Finding the atmosphere oppressive, Mr. Hajjat left two years ago to teach at the Free University of Brussels, in Belgium, where he said he found greater academic freedom.

“On the question of Islamophobia, it’s only in France where there is such violent talk in rejecting the term,’’ he said.

Mr. Macron’s education minister, Jean-Michel Blanquer, accused universities, under American influence, of being complicit with terrorists by providing the intellectual justification behind their acts.

A group of 100 prominent scholars wrote an open letter supporting the minister and decrying theories “transferred from North American campuses” in Le Monde.

A signatory, Gilles Kepel, an expert on Islam, said that American influence had led to “a sort of prohibition in universities to think about the phenomenon of political Islam in the name of a leftist ideology that considers it the religion of the underprivileged.’’

Along with Islamophobia, it was through the “totally artificial importation’’ in France of the “American-style Black question” that some were trying to draw a false picture of a France guilty of “systemic racism’’ and “white privilege,’’ said Pierre-André Taguieff, a historian and a leading critic of the American influence.

Mr. Taguieff said in an email that researchers of race, Islamophobia and post-colonialism were motivated by a “hatred of the West, as a white civilization.’’

“The common agenda of these enemies of European civilization can be summed up in three words: decolonize, demasculate, de-Europeanize,’’ Mr. Taguieff said. “Straight white male — that’s the culprit to condemn and the enemy to eliminate.”

Behind the attacks on American universities — led by aging white male intellectuals — lie the tensions in a society where power appears to be up for grabs, said Éric Fassin, a sociologist who was one of the first scholars to focus on race and racism in France, about 15 years ago.

Back then, scholars on race tended to be white men like himself, he said. He said he has often been called a traitor and faced threats, most recently from a right-wing extremist who was given a four-month suspended prison sentence for threatening to decapitate him.

But the emergence of young intellectuals — some Black or Muslim — has fueled the assault on what Mr. Fassin calls the “American boogeyman.’’

“That’s what has turned things upside down,’’ he said. “They’re not just the objects we speak of, but they’re also the subjects who are talking.’’