Police were initially informed at 4.40am on Sunday of a scooter burning in a square in front of the city’s train station.
The fire department doused the flames but the vehicle was destroyed along with a bicycle, police said.
Just ten minutes later, police learned that four cars were on fire on another street.
Fire-fighters arrived on the scene but the vehicles were destroyed before they could put out the blazes, which also damaged a nearby building.
Estimated damage is in the hundreds of thousands of francs, police said.
According to the results of an investigation by specialists with the force, the cars were torched intentionally.
Police could not immediately say whether the scooter fire was linked.
The arson follows a case last month when 20 vehicles were set alight intentionally, most of them in Biel’s Boujean neighbourhood.
Police are asking anyone with information about Sunday’s fires or suspicious activity around the train station to phone 032 344 51 11.