Largely organised by Catholic groups, Sunday’s demonstrations added to a weekend which saw opponents of proposed legislation, backed by the socialist government and due to be deliberated on in January.
The protesters say allowing gay marriages is a step too far.
“We already have the Pacs (gender-neutral civil union) for this, there are loads of measures which already exist. It seems the government is trying to destroy the family and social model,” said Bertrand Guerbet.
Scuffles broke out during at one event in Paris, as members of the Ukrainian group Femen let off harmless smoke and clashed with the anti-gay marriage demonstrators. Security used teargas to disperse those fighting.
The feminists are known for carrying out topless protests targeting religious institutions and against sex trafficking.