Hundreds of thousands of protesters turned out Sunday in Paris - some clashing with riot police - ahead of a final vote next month on same-sex marriage and adoption rights in France the BBC and The Guardian reported.
Some outlets also reported the anti-gay protesters took their children to the front of the protest to use as human shields, during clashes with police.
Police claimed 300,000 took to the streets in Paris in protest. The organizers, Manif Pour Tous, countered that 1.2 million participated.
In London, an estimated 2,000 people turned out to protest marriage equality in Trafalgar Square, an event also organized by Manif Pour Tous.
In Paris, the group had tried to stage the protest on the Champs Elysees, but were denied access to the route.
After the protesters broke through barricades on the historic street, police threw tear gas; according to reports, police arrested two people and no injuries were reported.
Some protesters called for the resignation of French President Francois Hollande, while others called on the president to focus on the economy and jobs, not same-sex marriage.
Last month, the lower house approved the "marriage for all" bill by a wide margin, 329-229. The final vote will take place in the upper house next month. Both houses are controlled by Hollande's Socialist Party and its allies.
Broad French support of same-sex marriage has recently eroded due to the ongoing anti-gay protest efforts.