The right to mock and caricature, even religion, is an essential part of being French, President Emmanuel Macron said at a naturalisation ceremony on Friday, days after the start of a trial of the accused accomplices in an attack by Islamist gunmen on the satirical magazine Charlie Hebdo in 2015.

In the Paris Pantheon, a mausoleum to France’s heroes, Macron handed five new citizens their French papers in a solemn ceremony to mark the 150th anniversary of the Third Republic.

“At the start of the trial of the attacks of January 2015, I say that to be French is to defend the right to laugh, jest, mock and caricature, of which Voltaire maintained that it is the source of all other rights,” Macron said. More than a dozen defendants went on trial this week for their role in the killing spree in the Paris offices of Charlie Hebdo, where 12 people died.

Welcoming five new citizens from Britain, Algeria, Cameroun, Peru and Lebanon, Macron said immigrants have long been a force for good in France, and noted that the Third Republic was proclaimed from Paris city hall by the son of an Italian immigrant, Leon Gambetta, on September 4, 1870.

“He was, like you, a son of immigrants, French of mixed blood. It was he who resuscitated the republic, this reign of freedom,” Macron said.

Macron said many other immigrants have shaped French history, including Polish-born scientist Marie Curie, American-born singer Josephine Baker, Tunisian-born feminist Gisele Alimi, and Felix Eboue, France’s first Black colonial governor and first Black man to have his ashes placed in the Pantheon.