PARIS — Hundreds of thousands of protesters marched in the French capital on Sunday in opposition to a gay marriage bill sponsored by President François Hollande.

Men and women, some with their children — along with a strong contingent of elderly people — assembled near the Arc de Triomphe and hoisted signs reading “Don’t touch marriage, take care of unemployment!” and “Everyone is born from a man and a woman.”

The police estimated that 300,000 protesters took part, 40,000 fewer than they said attended a similar rally in January, but organizers said 1.4 million people showed up. Among the marchers were prominent politicians from the main opposition party, the center-right Union for a Popular Movement, which has called upon its members to protest.

Near the end of the demonstration, small groups of young protesters tried to overrun barriers onto the Champs-Élysées, and the police fired tear gas to drive them back, The Associated Press reported.