Paris riot police fought back crowds who pushed their way on to Paris’s landmark Champs-Elysées avenue as part of a huge protest against a draft law allowing same-sex couples to marry and adopt children.

Hundreds of thousands of people – conservative activists, children, retired people, priests – converged on the capital yesterday in a last bid to stop the bill, many bussed in from the French provinces.

The lower house of France’s Parliament approved the “marriage for everyone” bill last month with a large majority, and it is facing a vote in the Senate next month.

Both houses are dominated by French President François Hollande’s Socialist Party and its allies.

Sustained protests led by opposition conservatives in this traditionally Catholic country have eroded support for the draft law in recent months, and organisers hope yesterday’s march will weigh on the Senate debate.

The first few hours of the protest were peaceful. But as it was meant to be winding down, about 100 youths tried to push past police barricades on to the Champs-Elysées, the avenue that cuts through central Paris and draws throngs of tourists daily.

In an indication of the sensitivity of the issue, protesters had been barred from marching on the Champs.

Police officers wrangled with the youths and then fired teargas to force them back.

Gaining momentum, more and more protesters took side streets to reach the avenue, blocking a key intersection on the route to the President’s Elysée Palace.

Police fired more teargas but were unable to block the crowds from spilling onto the avenue.

“Hollande, resignation!” the protestors chanted, before breaking into the French anthem, La Marseillaise.

The demonstrations have become outlets for anger and disappointment in Mr Hollande’s presidency.

An official with the Paris police headquarters said two people were arrested and no injuries were reported.