A French government spokesman was evacuated from his office as violence broke out during "yellow vests" protests in Paris and other cities.
Benjamin Griveaux said he and his team had had to escape through a back door after a construction vehicle was used to ram the building's entrance.
There were clashes between police and protesters on what was the first protest of the new year.
President Emmanuel Macron condemned the violence, urging "debate and dialogue".
What began as a protest about a fuel tax back in November has escalated into widespread anger at rising living costs.
The march in Paris began peacefully but scuffles broke out in the afternoon, with protesters throwing projectiles at riot police who responded with tear gas.
Motorcycles and bins were set ablaze, and a river boat caught fire.
Mr Griveaux said around a dozen individuals - some wearing black, some in yellow vests - used a small construction vehicle they found in the street to break through the door into the government compound. They also broke some windows and damaged some cars.
He and his team were led through a back entrance and took refuge in a hotel nearby.
President Macron tweeted his condemnation, saying France's "guardians, its representatives, its symbols" were being attacked.
Interior Minister Christophe Castaner said some 50,000 people had protested across France on Saturday - higher than last week but smaller than the 280,000 who turned out in November.
The protest began as a grassroots French provincial movement with people donning high-visibility jackets, which by law must be carried by every vehicle in France.
The movement, which became known as the "gilets jaunes" (yellow vests), broadened to include issues involving families' struggle to make ends meet, with calls for higher wages, lower taxes, better pensions and easier university entry requirements.
Mr Macron made a raft of economic concessions in December to appease the protesters. But he struck a defiant tone in his new year address to the nation, saying the government would push on with its reform programme, and would "make no allowances in guaranteeing public order."
Earlier this week, Eric Drouet, one of the leading public figures in the protests, was arrested for a second time on suspicion of organising an unofficial protest in Paris. His arrest prompted one political leader to call it an "abuse of power" by the government. He was released the following day.