French taxi drivers have blocked the roads to Paris airports and the main ring road around the city in a protest against Uber.
The drivers set up blockades and burned tyres as part of a nationwide strike.
Some cars were overturned and others had their windows smashed with bats.
Uber, a US taxi app, has been expanding its UberPOP ride-sharing service in France despite government objections.
Barriers also appeared around Marseilles and Aix-en-Provence in southeast France.
Aeroports de Paris, the operator of the French capital's Charles de Gaulle (CDG) and Orly airports, warned passengers to travel by train.
"Access by road is completely blocked," the company said on its website. "The only way to get to CDG is (by train)."
With traffic at a standstill in places, some travellers walked along the side of the motorway to reach the airport.
US musician Courtney Love Cobain was caught up in the unrest.
She tweeted saying her taxi had been ambushed and protesters were "beating the cars with metal bats". She also shared an image of the window of her taxi spattered with egg.
She later thanked two motorcyclists who had driven her away from the protest and said that she had been scared out of her wits.
we got out after being held hostage for an hour thanks to these two guys. I'm scared out of my wits.… https://t.co/cAOELz463U— Courtney Love Cobain (@Courtney) June 25, 2015
they've ambushed our car and are holding our driver hostage. they're beating the cars with metal bats. this is France?? I'm safer in Baghdad— Courtney Love Cobain (@Courtney) June 25, 2015
Taxi drivers also blocked access to Marseille and Aix train stations and protested on the main access to Marseilles-Provence airport.
The drivers - who have to pay thousands of euros for a licence - say they are being unfairly undercut by Uber, which is not licensed by the authorities.
Prosecutors have cracked down on Uber, filing almost 500 legal cases involving complaints about UberPOP. About 100 attacks on Uber drivers and passengers have been reported in recent weeks.
"Many taxis drivers are infuriated," Abdelkader Morghad, a representative of the FTI taxi union, told Bloomberg.
"We're demanding that the Thevenoud law, which clearly forbids unlicensed drivers, be implemented. There's a lack of political will to do it."
The law, which came into force in October, bans services that put passengers in touch with unregistered drivers. Uber has appealed against the rule, arguing that it gives licensed taxis an unfair advantage.
According to Mr Morghad, France's licensed drivers have lost between 30% and 40% of their income over two years because of the growth of Uber.
The San Francisco-based firm says it has a million users in France, including 250,000 for its basic UberPOP service. Uber also operates a luxury service which is not banned.
Uber has faced similar teething problems in cities all over the world, with traditional taxi drivers protesting against being undercut by the unlicensed company.
But licensed taxi drivers have been criticised for being slow to adopt the app-based geolocation technology behind Uber's success.