France and the defining moment
On four occasions the unions have held massive demonstrations but the legislation - raising the pension age from 60 to 62 - is winding its way through parliament. Within a couple of weeks it will have received final parliamentary approval and, after that, the time for protesting will be over.
So this round appears to be the critical one - the "defining moment" as many papers are describing it. Some of the unions are flirting with the nuclear option: a rolling strike where unions, particularly in the transport sector, vote for an open-ended strike beyond a strike on the 12th. On Saturday they are planning another day of protest.
As has happened before, the issue of controversial reform will be settled on the French street. In 1995 President jacques Chirac backed down over pension reform in the face of a three-week transport strike. And then in 2006, Prime Minister Dominique de Villepin withdrew employment contracts, after students turned out in huge numbers to fight the measures, which would have made it easier to remove workers.
So, if some unions go for an open-ended strike, it will be a straight clash between demonstrators and the government. The government has made its concessions; the unions have rejected them. As the paper Le Monde says "pension reform is the turning point in Sarkozy's presidency". "Failure," the paper added, "will sink him".
France cannot afford its current pension arrangements and this reform is intended to be a hallmark of Nicholas Sarkozy's presidency. If he were to back down he would be an empty suit, a bundle of energy without purpose.
His opponents are divided. Some are against a rolling strike. The UNSA union - drivers of the metro - have voted to work normally. However there are attempts to enlist high-school students in the protests. And then there is an ongoing strike involving port workers that threatens to close off fuel supplies. La Mede oil plant will have to shut down in a couple of days. Workers at most French refineries have backed rolling 24-hour strikes from 12 October. If France were to experience fuel shortages, the pressure on the government would mount quickly.
But polls suggest the public won't support rolling, wild-cat strikes that brings France to a standstill. President Sarkozy will be hoping that there is a silent majority who back him.
There are wider implications to what happens. It could influence others in Europe. On one level, there is not much sympathy for French workers who protest at a pension age going up to 62. Much of Europe is settling for a retirement age of 67.
Many other Europeans raise an eyebrow over the French refusal to compromise on what they see as the French way of life.
But this particular strike is a weather vane. If the protestors were to succeed it would embolden others. There have already been general strikes in Greece and Spain. A general strike is due in Portugal. In the UK, the rail union leader Bob Crow suggested that British workers follow the French in opposing pension reform.
So this is a critical moment. Increasingly workers are understanding that cuts may not be a one-off. Some countries like Spain and Ireland may have to embrace years of cuts to regain competitiveness, while the unemployment queues refuse to shrink.
Europe's unions know, too, that there are sharp divisions over the wisdom of embracing austerity. Cutting the deficits remains the new orthodoxy in Europe but there are plenty of economists who are arguing that demanding greater austerity will undercut the uncertain recovery.
So as the battle lines are drawn up in France, Europe will be watching.