Paris - Angry French taxi drivers blocked key roads with burning tyres and hundreds of flights were cancelled as air traffic controllers joined civil servants, hospital staff and teachers for a "Black Tuesday" of strikes.
At Paris's Orly airport, one protester was injured when a shuttle bus forced its way through a blockade, with the driver saying he "panicked". Police arrested the driver.
Some 2,100 taxi drivers, furious over upstart competitors such as Uber, blocked the capital's ring road at a key western intersection, lighting fires and throwing smoke bombs.
One Uber driver had his car splattered with eggs and kicked by protesters, an AFP journalist said.
"Today our survival is at stake, we are fed up of meetings and negotiations," said Ibrahima Sylla, spokesman of the Taxis de France collective.
"Before I'd have 10 to 12 fares per day. Now, it's just five or six," said Rahim Edalat, who has been driving taxis in Paris for 20 years.
"It's the worst year I've ever seen," he told AFP.
A total of 14 protesters were arrested around the capital for violence and lighting fires, police said.
"There is a right to protest... even during a state of emergency," said Prime Minister Manuel Valls, referring to measures imposed after the November attacks in Paris.
"But violence is unacceptable." Police advised motorists to avoid several areas of the capital, including Porte Maillot in the west of Paris where hundreds of taxi drivers had gathered with some intending to stay.
The taxi drivers kept up their action overnight and were continuing into Wednesday, with routes to Orly and Roissy airports also affected, police said.
Adding to the chaos, one in five flights in and out of Paris were cancelled because of a strike by air traffic controllers over pay and conditions, with the action affecting both Orly and Charles de Gaulle airports.
Budget airline Ryanair said it cancelled more than 200 flights, and easyJet cut 35 flights, mostly within France but also affecting Italy, Switzerland and Spain.
Air France said it would operate all its long-haul flights and more than 80 per cent of its short and medium-haul flights in France and elsewhere in Europe.
Last year, France banned Uber's low-cost UberPOP service - which used unlicensed drivers - but the professional version of Uber continues to operate legally, with taxi dispatchers in Paris saying business has shrunk by 20 to 30 per cent.
"Uberisation... is not just a Paris problem but a world problem," said Paris Mayor Anne Hidalgo, sympathising with regular taxi drivers who "must be able to make a decent living".
Uber flouted the UberPOP ban for several months, triggering a spate of violent protests in June.
The San Francisco-based company finally shut down the low-cost service in July after two of its French bosses were arrested and charged with "misleading commercial practices (and) complicity in the illegal exercise of the taxi profession".
At the same time, unions had urged some 5.6 million civil servants to down tools in protest over reforms that have already seen seven billion euros ($7.6 billion) in austerity cuts.
The government said only 10 per cent had joined the strike, but the hardline CGT union put the figure at nearly 30 per cent, describing the action as "the biggest mobilisation" of civil servants since socialist President Francois Hollande came to power in 2012.
In Paris, thousands of demonstrators marched with banners reading "Enough of austerity" and "Increase wages, not shareholders" with police putting the figure at 6,000 protesters while unions said turnout was around 15,000.
The strike also affected schools, with the education ministry saying more than 12 per cent of primary teachers had joined over demands for higher pay, as well as 22 per cent of high school teachers who are protesting against the reform of education for pupils aged between 11 and 15.
The striking unions - which led up to 120 demonstrations across France on a day dubbed "Black Tuesday" - said they were protesting over some 150,000 job losses since 2007, and demanded the creation of new positions, particularly in the hospital sector.
Farmers upset over falling prices also blocked roads with tractors in several rural areas and dumped manure outside some tax offices. Their unions are demanding distributors and major food companies pay more for produce and livestock.
Protests also took place in other French cities, notably Toulouse, Marseille and Aix-en-Provence in the south and Lille in the north, notably around railway stations and airports.