A French police officer stands guard as Muslims arrive at the Great Mosque of Paris after Friday prayers. (Thierry Chesnot/Getty Images)

The mournful sermon in the Mosque Tawhid at Friday prayers was about the attacks, because it is hard now to speak of anything else and dangerous to say nothing.

“Islam is completely against this abomination. To kill someone is to kill all of humanity,” the preacher, a member of the mosque named Abdallah, told dozens of men and women seated on the carpeted floor. “We all have an obligation to condemn these barbaric attacks. People need to hear that.

“If we don’t speak, certain people will ask questions.”

This mosque in the Paris suburb of Blanc-Mesnil was publicly accused last week by a politician in the neighboring town of radicalizing Samy Amimour, a 28-year-old who grew up nearby and was among the suspected gunmen at the Bataclan concert hall where at least 89 people died Nov. 13.

The Muslims who pray here were shocked by the accusation and its bluntness. Theirs was “a mosque known for being radical,” the neighboring deputy mayor, Jean-Christophe Lagarde, told the news media, “for being a place where they seek to radicalize the young.”

This mosque, long part of the surrounding community, where members distributed brochures deploring violence after the Charlie Hebdo attack, has been caught in the broad net of rumors, raids and deep suspicion surrounding France’s Muslims since the latest attack. Mosques across the country have been searched, as have individual homes in hundreds of “counterterrorism” searches not particularly linked to the Paris plot but conducted under the expanded police powers granted by the country’s current state of emergency.

The sweeping reaction comes in a country with a long-standing tension between the guarantee of religious liberty and a deeply felt political commitment to secularism — a tension that has been particularly acute for Muslims. In France, minarets are controversial, and girls are banned from wearing headscarves in public schools.

“The government reacted quickly and badly,” said Samy Debah, president of the Collective Against Islamophobia in France.

The government has been striving to reassure the French people by showing, very visibly, that it won’t tolerate even suspected signs of extremism. Polling data published over the weekend shows that 91 percent approve extending the state of emergency for an additional three months.

Assimilation is prized in France over the kind of “melting pot” ideal that exists in the United States. In France, the other is welcomed — if the other blends in.

“In France, do like the French. That means that you need to conform to a lifestyle shaped by centuries of Christianity,” legislator Marion Maréchal-Le Pen, the niece of far-right leader Marine Le Pen, said Saturday. “France isn’t a land of Islam.”

Other French politicians have echoed the hard line of their right-wing American counterparts. In August, after a foiled attack on a Thalys train bound for Paris, France’s transportation secretary, socialist Alain Vidalies, said he supported racially profiling passengers when inspecting travelers’ baggage.

Since the latest attacks, former president Nicolas Sarkozy has called for placing under house arrest — with electronic bracelets — roughly 10,000 people on a government list of residents suspected of posing security risks. Many of the people on the list, known as “fiche S,” have not committed crimes. According to complaints to Debah’s organization, others did not know they may be on the list until police visited them this week.

At the mosque in Blanc-Mesnil, government scrutiny is simply expected.

“We know that the mosques of France are under surveillance for a long time, but we have nothing to hide,” said Nassime Benmezroua, president of the Mosque Tawhid. Members say they have never seen Amimour, the suspected terrorist, let alone listened to sermons extolling violence. A few members are careful to explain that they, too, are French, as if the assumption outside the mosque is that they are not.

“We can never guarantee that someone came here or not, but when you say ‘radicalize,’ you mean something else, and I can assure you this never happened here,” Benmezroua said, responding to the accusations of Lagarde. “This mosque has been going for 15 years. Do you think we’ve been a recruiting center for the past 15 years? People would have known by now.”

For individuals, more so than institutions, the government intrusion can be even more unnerving.

Police searched the home last Tuesday night of Hervé Fraiture, a 35-year-old Belgian citizen and Muslim convert living in another suburb of Paris. Fraiture was in the living room of his apartment playing video games on his computer when his girlfriend heard noises outside.

“I quickly understood that it was the police and that they were going to blow my door open,” he said. “I shouted several times, ‘Wait, I’m going to open the door.’ ” They forced their way in anyway, he said — several armed officers and four plainclothes police officers.

In a search that he said lasted a couple of hours, police took photos of his books about Islam and scoured his computer. He explained to them that he had converted to Islam at age 16 and believed his religion condemned terrorism. His girlfriend, he adds, is agnostic.

“They would never have come after me if they’d checked who I really was. I don’t understand,” he said. “Is it because I’m a Belgian citizen and I’m a Muslim convert? Is it because a neighbor told the police that a Muslim lived next door?”

The police gave him an official document signed by the local police chief ordering the search of his apartment. The justification given: “There are serious reasons to believe that individuals, weapons or objects of terrorist nature could be found there.”