Commuters in Paris have been hit by a second day of strikes by French rail workers, with delays set to continue into Saturday.
There were more trains - but more commuters - as strikes continued
More trains were running - about a third of services - but with more commuters than on Thursday roads and rail services were clogged.
Unions hailed Thursday's strike as a success, saying 75% of staff took part.
The protest is over plans to end retirement privileges which let some workers retire at 50 on full pensions.
Two of Paris's main urban train lines would be severely disrupted on Saturday due to Friday's strike action, with intercity rail connections also suspended, the city's transport authority RATP said.
Two out of three metro trains would operate on Saturday, it said.
Two of France's eight transport unions extended the 24-hour strike, which began on Wednesday at 2000 local time (1800 GMT), for a further 24 hours.
Services were gradually returning on many train and metro lines on Friday, and Eurostar connections with London were operating as normal, state-run rail company SNCF said.
In Portugal for an EU summit, Mr Sarkozy said he was open to negotiations, but the pension reforms would go ahead.
"I am committed to this reform. It will happen," he said.
Mr Sarkozy says the special pension arrangements for some transport and energy workers are a relic of the past.
Union leaders will meet on Monday to decide whether to hold more large-scale strikes.
Opinion polls suggest that 60% of French people oppose the industrial action.
There have been fears that the ongoing strike action might delay fans travelling to the final matches of the rugby World Cup on Friday night and Saturday.
Union officials will meet on Monday to consider further action
But alternative rail and subway lines are operating to the stadiums.
On Thursday, several commuter rail lines were closed, bus and tram services faced disruption in 27 major cities, and just 46 TGV fast trains were running out of the normal 700.
With only one Parisian metro train in 10 running on most lines, the capital's new Velib self-service bicycle scheme recorded twice as many users as normal.
Thousands of striking workers marched through the streets, setting off firecrackers and sounding horns in one of several protests across the country.
The strikes are the biggest test so far of President Sarkozy's reform package.
His predecessor Jacques Chirac tried to abolish special pension regulations when he came to power in 1995, but backed down after three weeks of strikes.