French schools reopened Monday for the first time since the beheading of a teacher who opened a class debate on free speech by showing students caricatures of the prophet of Islam, in mourning and under tight security for a national homage.

Samuel Paty was killed on Oct. 16 outside his school in suburban Paris by an 18-year-old refugee of Chechen origin to punish him for showing the caricatures published by the satirical newspaper Charlie Hebdo, which triggered a newsroom massacre by extremists in January 2015.