PARIS (Reuters) - French demonstrators hit the streets in record numbers in their latest protest Tuesday over President Nicolas Sarkozy’s attempt to shake up the pension system, and striking transport workers badly disrupted trains.

Marches across France drew a higher turnout, police and unions said, than four earlier protests against Sarkozy’s plan to make people work longer for their pensions to curb a ballooning deficit in retirement coffers.

Yet Sarkozy, a dogged conservative who would benefit from getting his flagship reform passed before he takes on the job of G20 president in mid-November, looks unlikely to back down.

French media dubbed Tuesday the start of the “final battle” against the pension reform, which is on track to become law by the end of October. The reform will raise the minimum retirement age to 62 from 60, and lift it to 67 from 65 for a full pension.

The reform, which could help safeguard France’s cherished AAA credit rating as pension costs soar in the years ahead, has become one of the biggest battles of Sarkozy’s presidency.

It pits him against powerful unions which crushed a 1995 attempt to reform the system in a country that is fiercely attached to its generous social benefits system.

“This shows that people are firmly decided to oppose this reform,” Francois Chereque, head of the powerful CFDT union, said of the turnout as he led a march in central Paris.

Unions said 3.5 million people joined street marches, up from their estimate of 2.9 million in the October 2 demonstration, while the interior ministry put the number at 1.23 million, a rise of nearly a third.

The latest round of strikes disrupted air and train travel and shut the Eiffel Tower during the afternoon for lack of staff. Unions are threatening more open-ended walkouts, but Sarkozy’s government is vowing not to cave in.

“We have reached the limit of the (concessions) that are possible,” Prime Minister Francois Fillon said.

Last week Sarkozy offered a concession in the reform to mothers close to retirement age who give up work to raise several children, and analysts doubt he would give up much more ground.

“It’s part of the ritual but nonetheless impressive,” said Gilles Moec, an economist at Deutsche Bank in London. “Probably not enough to block the pensions bill, but enough to block any further structural reform.”

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EIFFEL TOWER SHUTS

Walkouts reduced flights from Paris’s main airports by as much as 50 percent. One in three high-speed TGV trains were running, though international trains operated more frequently.

The Paris metro ran limited services, sea ports were disrupted and oil refinery closures due to related dock worker strikes raised the specter of fuel shortages.

Students, concerned that making older people work longer will shut off job opportunities for them, chanted slogans, waved banners and climbed onto the roofs of bus shelters with loudspeakers. There were protests at about 300 schools.

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“This law ignores the reality for young people,” said Eloi Simon, 21, a student near Paris. “It’s hard enough to find a stable job and if this goes through it will be even harder.”

Spending cuts across deficit-plagued Europe have sparked angry protests, most notably in Greece and Spain.

France’s parliament has now passed the core clauses of the pension bill, on lifting the retirement age, and Sarkozy is now betting on protest action waning in the coming days, especially among those who lose pay when they walk out.

Unions are planning more action for Saturday and some have threatened rolling strikes in the days ahead.

“The action is not going to stop because senators have voted. Today we have an even bigger encouragement to continue,” said Bernard Thibault, head of the CGT union.

Budget airline Ryanair urged the European Commission to ban strikes by what it called “overpaid, underworked” air traffic controllers after it was forced to cancel 250 flights.

“Striking French ATC staff are the modern equivalent of highwaymen,” outspoken chief executive Michael O’Leary said.