Trouble started late Saturday when 50 opponents of gay marriage were arrested in central Paris, according to police.
France's Constitutional Council threw out a legal challenge by the right-wing opposition to the new bill, which also legalises gay adoption.
At the same time dozens more protesters assembled on the pavement waving flags.
In total 50 people were held and a van carrying masks, banners and smoke bombs was seized, police said.
The police received criticism for their handling of of recent violence on the streets if Paris after a celebration near the Eiffel Tower by Paris Saint-Germain football fans, to mark the club's league victory, turned violent, with some tourists attacked in the heart of the city.
Far-right writer and activist Dominique Venner shot himself dead in front of the altar of Paris's famed Notre Dame Cathedral on Tuesday, leaving statements denouncing gay marriage and immigration.
In a final essay on his website, Venner had railed against France's adoption of the "vile law" legalising gay marriage and adoption.
Gay rights watchdog SOS Homophobie has hailed the legalisation of gay marriage while decrying the wave of homophobic protest which has followed it.
"Our country has taken a great step forward today although it's regrettable that it was taken in a climate of bad faith and homophobic violence," it said.
The most radical protesters have joined a nebulous umbrella group "Printemps français" (French spring), which the French interior ministry has threatened to dissolve due to its inflammatory rhetoric.