Paris police fired tear gas and taxi drivers lit bonfires on a major highway Tuesday amid nationwide strikes and protests over working conditions and competition from non-traditional services such as Uber. The strike also involved air traffic controllers, disrupting flights throughout the country.

Tuesday’s protests are the latest challenge to the Socialist government as it tries to modernize the economy and find France’s place in an increasingly globalized, online marketplace.

One in five flights were cancelled at Paris airports and other flights faced delays as air traffic controllers staged a walkout and taxi drivers disrupted roads. Twenty people were detained at protests around the French capital, according to Paris police, and i-Tele television reported that two people were injured at Orly Airport when a shuttle bus tried to force its way past a taxi drivers’ blockade.

Hundreds of French taxis, joined by a few from Belgium and Spain, blocked a massive intersection leading into western Paris. Dozens of taxi drivers tried to march onto an eight-lane bypass, but police pushed them back with tear gas. Some drivers set pre-dawn bonfires, put out later by firefighters.

Traditional taxi drivers say they’re suffering unfair competition from Uber, which has faced legal challenges around Europe.