PARIS—President Emmanuel Macron on Wednesday ordered France into its third national lockdown and said schools would close for three weeks as he sought to push back a third wave of COVID-19 infections that threatens to overwhelm hospitals.

Tables and chairs are seen in a closed classroom at the private primary school Jeanne D'Arc in Saint-Maur-des-Fosses, near Paris, amid the CCP virus outbreak in France, on March 30, 2021. Gonzalo Fuentes/Reuters