Police in Paris arrested 50 opponents of gay marriage on Saturday, a day before foes are expected to stage a major protest against a recently approved French law making it the 14th nation to legalize such unions.

Demonstrators lined along the Champs-Elysees, chaining themselves to metal barriers they placed in the middle of Paris' famed boulevard. Dozens more protesters stood by waving flags.

According to the AFP, some protesters fired smoke canisters before police hauled them away. Police also seized a van carrying masks, banners and smoke bombs.

Despite the arrests, the incident passed without violence.

Sunday's demonstration is expected to attract 20,000 demonstrators and comes just two days before the legislation is set to take effect on Wednesday. It is sponsored by the group Manif Pour Tous (Demonstration For All), which is helmed by Frigide Barjot.