The CGT (General Confederation of Labour) union said more than 1million people took part in demonstrations, although the figure provided by the Interior Ministry stood at 500,000.
Many joined strikes across the country, with pharmacies, schools and public transport all affected significantly.
Numerous street blockades were set up in the morning at bus depots, traffic hubs and secondary schools, while dozens of protesters briefly stormed the courtyard of the Ministry of Economics.
More than 180 people were detained nationwide, with 30 arrests in Paris.
The protest was intended to put pressure on new Prime Minister Sebastien Lecornu, who is deliberating over a new austerity budget after the collapse of the previous government earlier this month.
The strikes were called by an alliance of unions, who argued that the measures threaten the livelihoods of workers, pensioners, and low-income households.
A proposal to eliminate two public holidays has been the target of particular criticism, although Lecornu has already announced that the measure would be dropped.
France is suffering from a prolonged budgetary and political crisis.
The country has the third-highest ratio of debt to gross domestic product in the European Union, at 114%. — dpa
