French police on Monday raided the homes of dozens of suspected Islamist militants three days after the beheading of a teacher who had shown his pupils cartoons of the Prophet Mohammed, the interior minister said.

The raids came a day after tens of thousands of people took part in rallies countrywide to honour slain French history teacher Samuel Paty and to defend freedom of expression.

Interior Minister Gérald Darmanin said the swoop on Islamist networks was designed to send a message that “enemies of the Republic” would not enjoy “a minute’s respite”.