French officials have opened an investigation into the attempted murder of a police officer and Germany’s interior minister has called for harsh penalties after peaceful and mainly youth-led protests across Europe ended in violence.

In Portugal, police – some with dogs – cleared protest camps with baton charges, while security forces in Switzerland were attacked with paving stones.

Protests over the education system, deteriorating public services, declining prospects, unaffordable housing and the spiralling cost of living have shaken a number of countries this autumn.

Violence erupted in the French capital as well as Marseille, Grenoble, Bordeaux, Lyon and Toulouse on Saturday night after an estimated 320,000 demonstrators, some in Halloween costumes, took to the streets.

Protesters in Halloween costumes gather in the La Plaine square in Marseille. Officials say 320,000 people took part in protests across France.…