The high school in Arras, northern France, where a teacher was fatally stabbed on Friday was evacuated on Monday morning following a bomb alert.
While there were no classes scheduled at the Lycee Gambetta high school, its doors were open for pupils and staff to pay tribute to teacher Dominique Bernard.
As a police bomb squad arrived, teachers, some of them in tears and holding each other, and pupils gathered in the courtyard of a building opposite their school as civil protection personnel comforted them.
A 20-year-old man fatally stabbed a French teacher and wounded two other people in an attack on Friday at Lycee Gambetta in an attack that President Emmanuel Macron condemned as "barbaric terrorism".
France was put on its highest security alert following the attack.
A minute of silence is planned for later in the day in schools across the country.
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