The public seemed to take it for granted that gay marriage should be a part of British life. It was perhaps a sign of how Britain has evolved in past decades into a much more cosmopolitan nation than its starchy, traditionalist image would suggest.
"The opposition seemed restricted to a very small number of people very vigorous in their views," said Steven Fielding, a political scientist at the University of Nottingham. "It was restricted to the back benchers of the Conservative Party. It wasn't shared across the political spectrum. It was an issue whose time had come. To oppose it seemed slightly strange."
The law was also written in a way that allowed the Church of England - which is opposed - to sidestep the controversy since it is explicitly barred from conducting same-sex marriages.
The picture was completely different in France. Few people had expected legalising gay marriage to face much of a hurdle. French polls had shown for more than a decade that the concept enjoyed majority public support, and Paris has had a gay mayor for years.
And to outsiders, of course, France is seen as the land of "anything goes" when it comes to sex from the Marquis de Sade to author Colette to disgraced French politician Dominique Strauss-Kahn, notorious for his libertine sex parties.
Politically, too, it was meant to be a blip. Legalising gay marriage was near the bottom of French President Francois Hollande's 36-point agenda for his presidency. It was mentioned in passing during his presidential campaign but was never an issue that galvanised opposition, and was entirely eclipsed by concerns about the economy.
Then, something clicked in the conservative heartland - which showed just how much of a force it is in French life.
When the law was drafted and the idea of gays marrying turned from concept to imminent reality, traditionalists spoke up, and loudly. Protests grew bigger, and spread wider. Opponents of the bill stirred up fears about gay parents raising France's new generations.
A fringe of far-right skinheads drew camera crews and condemnation as they wrestled with riot police at Paris protests. But most of those at the barricades were families, children with grandparents, members of France's minority of practicing Catholics bussed in en masse from towns and villages to march on the capital. Some conservative Muslims and Jews joined in.
In marching against gay marriage, the demonstrators also seemed to be protesting freewheeling Paris life, the image of a wanton, insatiable French sexuality celebrated in films and art - but far from the reality of many provincial French families. For a time in early 2013, France felt like a deeply divided nation.
But the size of the anti-gay marriage movement was largely the result of a political backlash against Hollande, whose popularity dived soon after his election over his handling of the economy.
The movement was the right vehicle at the right time to target Hollande and his Socialists. Once the law passed, the momentum stalled.
Even the protesters seemed to realise they remain the minority, and polls continue to show that most French people think gay marriage now that it is a fact of life is fine.
- AP