Video | Sarkozy defiant as Unions announce more strikes in France

Despite growing pressure, Sarkozy held firm on a measure he says is crucial to the future of France, heightening the standoff with labour unions that see retirement at 60 as a hard-earned right.

Weeks of protests have left at least a quarter of the nation's gas stations on empty, blocked hundreds of ships at the Mediterranean port of Marseille and even forced Lady Gaga to cancel Paris concerts.

Violence on the margins of student protests have added a new dimension to the volatile mix.

A march in Paris by at least 4,000 students was peaceful, but new violence broke out in Lyon, where police used water cannon and tear gas to hold back rampaging youths hurling bottles and overturning at least one car.

The tough talk extended to parliament where the government short-circuited a protracted debate on the retirement bill by ordering Senators to vote on a package of its own design.

The French government - like many heavily indebted governments around Europe - says raising the minimum retirement age from 60 to 62 and overhauling the money-losing pension system are vital to ensuring that future generations receive any pensions at all.