French Interior Minister Nicolas Sarkozy has ordered police to be on maximum alert in areas where outbreaks of violence could occur.
Law and order is a major presidential election issue |
Several buses have been torched in the run-up to the anniversary of last year's widespread rioting in suburban areas.
Mr Sarkozy said that all "sensitive" bus routes would be protected.
"We will do everything possible to ensure that public services are not disrupted anywhere," he said.
This time last year saw three weeks of violent clashes between youths of mainly North African origin and police in suburbs throughout France, when more than 10,000 cars were set alight and 300 buildings firebombed.
Thursday saw armed youths hijack and set fire to a bus in the suburbs of Paris, while hooded gangs torched two others on Wednesday night.
Mr Sarkozy, a conservative front-runner in next year's presidential election, said the media should act responsibly in reporting on the anniversary of last year's violence, to avert "copycat" crimes.
"We should not give any publicity to people who want nothing else," he said.
A security services report leaked to a French newspaper this week said that the conditions that led to last year's riots were still in place.
Law and order has become a major issue, with presidential elections due next year. Candidates from the two biggest parties have promised a tough approach to crime.