MARSEILLE, France—Police in the French city of Marseille detained a man Friday who was wielding a knife outside a Jewish school and kosher market. Surveillance of Jewish sites in the city has been increased while they investigate his motives, according to local authorities.

A police officer guards a Jewish school after a man visibly brandished a knife outside a Jewish school and a kosher market in Marseille, southern France, on March 5, 2021. Daniel Cole/AP Photo