Police and demonstrators clashed this Sunday in several cities in the Netherlands on the sidelines of rallies against the curfew.
In Eindhoven, in the south of the country, the security forces used tear gas to disperse a crowd of several hundred people and respond to the jets of projectiles.
About 30 people were arrested, according to local police.
Several vehicles were set on fire and businesses in the central station were looted.
Other cities have been the scene of clashes.
In Amsterdam, a water cannon and police dogs were deployed.
A Covid-19 testing center was set on fire on Saturday evening in the village of Urk, in the north of the country, as the national curfew imposed by the government came into force.
To fight Covid-19, the Netherlands began their first curfew on Saturday since World War II.
It is forbidden to leave your home between 9 p.m. and 4:30 a.m., at least until February 9.
According to Prime Minister Mark Rutte, this curfew must avoid confinement, while since the start of the health crisis, the Dutch have never had to justify their movements.