Paris police fired tear gas on Thursday to force protesters away from the headquarters of President Emmanuel Macron's centrist party as a strike against his pension reforms continued.
Dozens of protesters had to flee thick clouds of tear gas in the narrow streets near the Paris Opera.
The head of Macron's La Republique en Marche party, Stanislas Guerini, condemned what he described on Twitter as an "attempted intrusion by radicalised demonstrators" at the party's offices.
A police source confirmed that protesters had tried, without success, to get into the party offices. Three people had been arrested during an undeclared demonstration nearby, police said.
In a televised New Year's Eve address, Macron said he expected Prime Minister Edouard Philippe to find a compromise on the pension reforms with "the trade unions and employer groups who desire it."
But trade unions were unimpressed with his statement, which offered no specific concessions on plans to replace existing professional pension schemes with a single national scheme and raise the standard age for retirement on a full pension from 62 to 64.
The head of the hardline CGT trade union, Philippe Martinez, told RMC radio on New Year's Day that he was calling on "all the French people to mobilise, to protest and to go out on strike."
Earlier in the week, a CGT official told public broadcaster FranceInfo that the union was planning to blockade the country's fuel refineries from January 7 to 10.
Train services and Paris public transport have been disrupted by strike action since December 5 - now the longest-ever strike in the history of state railway company SNCF, according to French media.