French police and protesters clashed in central Paris during a demonstration billed as being 'in defence of public services'.
Trade unionists are angry at years of public sector pay curbs and President Emmanuel Macron's economic reforms.
Riot police fired stun grenades and tear gas. Two shops and a bus stop were destroyed in the violence. Twenty people were arrested.
It's the third time that labour unions have sought to stage a nationwide show of strength in this fashion since Macron began his five-year-term in May last year.
Tuesday's call came from all large labour unions and many smaller ones and involved the staging of street rallies in about 140 cities and towns across France.