Pension rallies hit French cities
Officials said 1.1 million people had joined protests, but unions claimed the figure was 2.5 million.
The activists are angry at government plans to overhaul pensions and raise the retirement age from 60 to 62.
France's retirement age is lower than many countries in Europe, but analysts say the issue is polarising politics in the country.
End Quote Gavin Hewitt BBC Europe editorThe atmosphere is good-humoured, almost carnival. But this is a very serious day for the French unions”
Under current rules, both men and women in France can retire at 60, providing they have paid social security contributions for 40.5 years - although they are not entitled to a full pension until they are 65.
The government says it will save 70bn euros (£58bn) by raising the retirement age to 62 by 2018, the qualification to 41.5 years, and the pension age to 67.
President Nicolas Sarkozy says reforms are needed to cope with an ageing population and the country's budget deficit.
EUROPE'S RETIREMENT AGES
- France - 60
- UK, Italy - 65 for men, 60 for women
- Germany, Netherlands, Spain - 65
- Greece - 65 for men, 62 for women
State railway operator SNCF said fewer than half of its TGV high-speed services were running, and there was a greatly reduced service on many other lines.
Eurostar said its trains between France and London would operate normally.
Some air-traffic controllers walked out, forcing the cancellation or delay of about a quarter of flights from Paris airports.
Air France said it was operating all of its long-haul flights as planned, but short and medium-haul flights had been affected.
Amid the disruption caused by strikes, the Interior Ministry said 1.1 million people had joined Tuesday's protests - making it a bigger protest than a previous one in June, where more than 800,000 people took part.
Huge crowds braved stormy weather across southern parts of France, while demonstrators in Paris and the north enjoyed autumn sunshine.
In Paris, protesters shouted through loud-hailers: "Slave-driving? No, no, no. Working more? No, no, no. Fair reforms? Yes, yes, yes."
Protester Michel Prouvier told AFP news agency: "We're going to have old people living in the street."
Activists were also keen to maker a wider point, angry at the recent deportation of about 1,000 Roma (Gypsies) and a host of proposed laws which they say unfairly target immigrants and minorities.
"Pensions are a pretext for protesting against the Sarkozy system," said Adji Ahoudian, a Socialist Party activist.
Among those concerns is a proposal banning the full face veil worn by Muslim women, which was passed by the lower house in July but is now up for debate in the Senate.
Senators are also expected to debate a controversial new security law which would see recent immigrants stripped of French citizenship if they committed serious crimes such as killing a police officer.
The law would also allow electronic tagging for foreign criminals facing deportation.