Protests have turned violent in France after at least 250,000 people rallied against a controversial new labour law. The worst violence erupted in Paris, where riot police fired rubber bullets and tear gas. Public disorders spread also to some of the other 80 cities holding rallies. A newspaper stand and a number of cars were set on fire and protesters at the symbolic Sorbonne University pelted police with stones and bottles and chanted slogans comparing them to the Nazi SS. About 150 protestors were arrested in the aftermath, police said. Protesters object to new two-year job contracts for under-26, which employers can break off without explanation. President Jacques Chirac has appealed for talks, but says the new law is important to fight unemployment.