Police clashed with rioters in Basel and Chur overnight, but Zurich was calm, despite fears that violence could break out at an illegal rave announced for Saturday.
Basel police said on Sunday they had received a stream of calls complaining about the noise being made by about 100 people who had gathered in one of the outlying squares.
The rioters had set building materials on fire, and when the fire brigade arrived, some masked rioters had started smashing the windows of nearby shops. As soon as they police came, they had run off.
Two people had been arrested.
The police were kept busy in Chur, the capital of the southeastern canton of Graubünden, after the Schlager music parade, which drew a record 30,000 people on Saturday afternoon.
City police said that the event itself passed of peacefully, but that they had been called out several times during the night to deal with people, mostly drunk, who were acting violently and causing damage.
Police had been on standby in Zurich, after two weekends of violence by illegal party-goers, but Saturday night was calm despite the fact that text messages had been circulating inviting people to an illegal rave in the city.
Last weekend 91 people were detained, of whom about 20 are still in custody. Most are Swiss aged between 18 and 25.
swissinfo.ch and agencies