But the walkouts looked increasingly like the last gasp of a protest movement that started with train drivers but seemed to be losing punch after a week of major travel disruptions.
Talks with transport unions were to start Wednesday and the government said it would take part.
Tuesday marked the seventh full day of the transit strikes against pension reforms.
Hundreds of thousands of civil servants teachers, customs agents, tax inspectors and the like also stayed off the job Tuesday to press for pay hikes and job security. Sarkozy has promised to slim down and reform the civil service, France's largest employer, with more than 5 million workers.
Although civil servants and transport workers have different demands, together their protests presented the biggest test yet of Sarkozy's determination to revamp France with reforms and cost-cutting.
More than 300,000 teachers or nearly 40 percent of the total were on strike Tuesday, the Education Ministry said, forcing some schools to close. Postal services were also affected.
National newspapers were absent from kiosks Tuesday as printers and distributors jumped on the strike bandwagon. Strike-hit France-Inter radio broadcast music and a message of apology instead of its regular programming.
National weather service Meteo France, which has 3,700 employees, said a third of its staff who were scheduled to work Tuesday were on strike, but weather forecasts were not affected.
Thousands joined protest marches in Paris and other cities. The Paris demo had a picnic atmosphere, with music, roasted sausages and balloons marked "Public Service is a Public Good." The demonstrators were marching across the Left Bank to the gold-domed monument at Les Invalides, site of Napoleon's tomb.
About one employee in seven at France's main energy utilities, Electricite de France and Gaz de France, was on strike, the companies said.
Striking air traffic controllers caused delays averaging 45 minutes at Paris' two airports, Charles de Gaulle and Orly, affecting a variety of flights, from short domestic routes to long-haul.
Despite the pressure on Sarkozy, the government has stood firm. Prime Minister Francois Fillon said Monday that reforms must move forward.
The transit strike has caused massive disruption on the national rail network and in Paris' Metro and commuter lines.
The government says the transit walkout is costing France's economy between Ђ300 million and Ђ350 million (US$440 million and US$513 million) a day and could dent economic growth if it lasts.
Train drivers are protesting Sarkozy's plans to extend their retirement age. The government has insisted that for talks to start, unions must move toward a return to work. It also says the core of the reform that all workers must work for 40 years to qualify for full pensions is nonnegotiable.
Sarkozy has often jumped into trouble spots to fix them himself but has remained curiously silent about the strikes, perhaps to avoid stoking the protesters' determination.
The conservative was elected on promises to reform France from its courts to its creaking university system, its army of civil servants to rail workers whose special retirement privileges he vowed to eliminate.
Campuses are also bubbling with discontent. Knots of students have been blocking classes at dozens of France's 85 state-run universities to protest a law allowing them to seek nongovernment funding. Critics fear the change will mean schools closing their doors to the poor and scrapping classes that can't attract private funding.