The Ivory Coast government has appealed for calm after violence rocked the country's economic capital, Abidjan.
President Gbagbo's supporters have attacked western targets in the past
Police used teargas on Monday to disperse supporters of President Laurent Gbagbo who attacked United Nations sites.
They were angry at international mediators, who say that parliament, loyal to Mr Gbagbo, should stand down.
Demonstrations continued outside the French embassy into the evening, despite a ban on street protests.
Interior Minister Joseph Dja Ble appeared on national television to urge Ivorians to remain calm.
On Sunday, the UN-appointed mediators overseeing the peace process said the mandate of MPs should not be extended.
Elections due in October were postponed because of continued instability.
The UN has extended the mandate of Mr Gbagbo for another year, so that elections can be organised, while a power-sharing government runs the country.
During the day hundreds of protesters gathered in front of the United Nations mission headquarters near the city centre chanting "Respect Gbagbo's power".
Some shops and schools closed for the day because of the protests.
The BBC's James Copnall in Abidjan says the national assembly is one of Mr Gbagbo's last power-bases.
Our correspondent says Mr Gbagbo's supporters feel that if parliament's mandate is not renewed, it would mean the constitution was not being respected and that foreigners were imposing their will on Ivory Coast.
Analysts say the international working group's move was intended to strengthen the authority of Prime Minister Charles Konan Banny's authority and ensure that hostile deputies do not block attempts to implement the peace process, as happened last year, the AFP news agency reports.
On Monday evening, supporters of the president known as the Young Patriots organised a sit-in in front of the French embassy.
Their leader Charles Ble Goude told the BBC that France - the former colonial power - was behind the international working group's decision.
The Young Patriots have attacked French citizens in the past, most notably in November 2004 when more than 8,000 Westerners were evacuated.
The rebel New Forces have controlled northern Ivory Coast since September 2002.
Some 10,000 French and African peacekeepers are in Ivory Coast.