Paris - French authorities were wary of violence spilling over from Greek youth protests as thousands of secondary-school students protested Thursday throughout France against a proposed education reform plan.

Some 3,500 students took to the streets in the western city of Rennes, while in Brest youths tossed stones at police, who responded with tear gas, the online edition of the daily Ouest France reported.

Demonstrations of several hundred students to a few thousand took place in many French cities Thursday, continuing a week of protest against the proposed cutting of more than 13,000 teaching posts next year.

Students have called for a national day of protest on Friday, at which disgruntled teachers and parents are also expected to take part.

On Thursday, former prime minister Laurent Fabius warned that the demonstrations could grow more violent.

"What we are seeing in Greece is, unfortunately, not at all out of the question for what could happen in France," he told Europe 1 radio.

On Wednesday, violence linked to the Greek anti-government protests broke out in Rome and Bologna in Italy and in the Spanish cities of Madrid and Barcelona. (dpa)