Two vehicles owned by the Circus Knie caught fire in Nyon in the early hours of Sunday morning.
Police say they believe the fire was intentional - but the circus was not the target.
It had been set up on the Place Perdtemps.
The fire broke out far away from the marquee and the animals. No one was hurt.
Vaud cantonal police say they think a nearby construction site was the objective of the arsonists.
Search for missing man in Rhône
Emergency services are searching the Rhône in Geneva tonight for a young man who failed to resurface after jumping into the river with three friends.
Geneva worst for traffic
Geneva is now the most congested city in the country, with Lausanne in third place.
Geneva's cross-border compensation payment to France reaches record CHF 411m
Geneva will transfer a record CHF 411 million to France this year under the Financial Compensation scheme, up from CHF 396 million last year.
Crans-Montana bar accountant facing criminal allegations
The investigation into the deadly Crans-Montana bar fire has taken a sharp new turn.
Geneva tops list for cocaine use
Cocaine use in Switzerland continues to rise, according to a new study by Addiction Switzerland.
Bol d'Or rocked by controversy
Controversy has overshadowed the 87th Bol d'Or sailing competition this weekend.
