PARIS — In 2015, the rallying cry was "Je suis Charlie." Now, it is "Je suis Samuel."

Samuel Paty, the middle school history teacher who was beheaded after having shown his students caricatures of the prophet Muhammad during a lesson on free expression, was posthumously granted France’s highest award, the Légion d’Honneur, and commemorated in a national ceremony at the Sorbonne University in Paris on Wednesday.

His gruesome killing in the Paris suburb of Conflans-Sainte-Honorine has revived the nation’s horror at the 2015 attack on the offices of Charlie Hebdo. And just as France stood by the satirical newspaper then, it is rallying around its teachers.

At the ceremony in Paris, President Emmanuel Macron called Paty “the face of the Republic,” eulogizing a man whose “apartment was a library” and whose “greatest gifts were books.”

“We all have, in our hearts, in our memories, a teacher who changed the course of our existence,” Macron said. “You know, this teacher who taught us to read, to count, to have confidence in ourselves. This teacher who not only passed on knowledge to us but opened a path for us.”

“Samuel Paty was one of those,” he said, “one of those teachers who will not be forgotten, of these enthusiasts capable of spending nights learning history, a teacher who questioned himself a thousand times, as he did for a course on freedom of expression and freedom of conscience that he had been preparing since July.”

Whereas Charlie Hebdo relishes causing offense in its pursuit of free speech, Paty — according to the accounts of those who knew him — did not.

He attended training courses at Paris’s Arab World Institute to better understand his students. He organized an Arab music concert to honor their culture.

“He had read the Koran and respected his students, regardless of their beliefs,” Macron said. “He was interested in Muslim civilization.”

And when he introduced the topic of the controversial cartoons in class, he acknowledged that it might be hurtful to Muslim students and offered them a chance to look away.

On Wednesday, Jean-François Ricard, France’s anti-terrorism prosecutor, provided a clearer picture of how officials say Paty was targeted and killed.

After the Oct. 5 lesson on free expression, one parent — whose daughter was not actually present in Paty’s class that day, Ricard said — complained on social media, and prosecutors say that is how the episode came to the attention of the attacker, Abdoulakh Anzorov, an 18-year-old Russian-born Chechen who lived 50 miles away.

Ricard said the parent’s Facebook posts included Paty’s name and the name of the school where he taught, the Collège Du Bois d’Aulne. Anzorov and the parent exchanged multiple telephone and written messages in the weeks leading up to the attack, Ricard said.

But he said Anzorov could identify Paty only with the help of students. “The identification was possible through the intervention of schoolchildren,” Ricard said.

Police shot and killed Anzorov shortly after the attack. Seven people were set to go before a judge Wednesday, Ricard said. Included were two minors, ages 14 and 15, who helped Anzorov identify Paty in exchange for about $350, according to the prosecutor.

Also among those who have been detained are the father who posted about Paty and cleric Abdelhakim Sefrioui. Interior Minister Gérald Darmanin has accused both of launching a “fatwa,” or religious order, against the teacher. And Sefrioui’s organization, the Cheikh Yassine Collective, is being ordered to disband.

The killing has provided further impetus for a French government effort to rein in radicalization and — controversially — to “reform” how Islam is practiced in France.

Macron, speaking Tuesday in the Paris suburb of Bobigny, said, “Several dozen concrete actions have been launched in recent days against organizations, associations or individuals who carry a project of radical Islamism, or an ideology of destruction of the republic.”

While the French are shocked by Friday’s attack, some have questioned whether the government is going too far with its crackdown — conducting raids, threatening deportations and targeting organizations with tenuous connections to Paty’s killing.

The government ordered a mosque in the Paris suburb of Pantin to close for six months for having shared on Facebook a video calling for action against Paty. The mosque deleted the video and expressed regret.

“There’s no room for violence in our religion,” the Pantin mosque said Monday in a Facebook statement. “We strongly condemn this savagery.”

Darmanin, meanwhile, signaled that more than 50 French Muslim organizations are under scrutiny and would be shut down if found to be promoting hatred. And he specifically threatened to dissolve the Committee Against Islamophobia in France (CCIF), characterizing it as an enemy of the republic.

The CCIF acknowledged in a statement that it was contacted by the parent about Paty and had been looking into his claims, but it denied participating in a harassment campaign against the teacher.

An umbrella group, the European Network Against Racism, expressed concern about Darmanin’s statement.

“This proposal to dissolve a professional anti-racist organisation which does crucial work to combat racism and defend the rights of racialised groups is a violation of democratic freedoms,” the organization wrote. “. . . It reflects institutional racism within the French government, in a context where it has recently announced a bill which stigmatises and targets French Muslim communities.”