Prime minister Manuel Valls has promised a tough response after members of a community of travellers went on the rampage in south-eastern France, reports the BBC.
Cars were burned in Moirans as dozens of protesters vented their anger at a judge's decision to deny a young man leave to attend his brother's funeral.
Mr Valls condemned the "unacceptable violence" and demanded "extreme firmness" in dealing with rioters.
No-one was hurt in the violence but the disruption halted local train services.
The railway line at Moirans between Grenoble and Lyon was cut and a main road in the Isere area was also blocked by burning cars.
The prime minister said those involved would be pursued relentlessly.
The funeral went ahead on Wednesday afternoon, reports said, days after the young man was killed in a crash involving a stolen car. Two other people died in the accident.