It started on a drizzly June day in 1979, when 500 people holding home-made signs marched past surprised West Berliners.

On Saturday, half a million people are expected to brave 33-degree heat to march in the 40th anniversary Christopher Street Day, Germany biggest gay pride parade.

Behind the sweaty glitter and sparkling wine, however, campaigners in Europe’s gay mecca are sounding the alarm. A year after Germany secured marriage equality, community leaders see indications of rising apathy – even anger – towards homosexuals.

“There’s this strange mood in German society now, with people saying ‘you got marriage equality, what else do you want?’” said Johannes Kram, author of a new book called “I’ve Nothing Against Gays, But . . .”

Behind the “but” he sees what he calls a “terribly civilised homophobia” of people who denounce homosexuals in public as a privileged elite, spoiled in recent years at the expense of the working class or other deprived groups.

“As part of this new narrative,” said Kram, “those that threaten us – usually straight men who have problems with their own sexuality – are portraying themselves as an oppressed victim group who cannot express how they feel.”

Despite Berlin’s largely liberal and tolerant culture, gay counselling and victim support centre Maneo notices a rise in numbers seeking its services.

It dealt with 800 cases last year and, of 407 it was able to analyse more closely, found that 324 fulfilled their definition of homophobic or transphobic attacks: physical attacks, verbal abuse and theft.

Scale of homophobia

No representative surveys are possible as many victims are reluctant to come forward, making it impossible to quantify the real scale of homophobia, let alone whether it is growing or falling.

“But the figures we have show we still have a shocking daily reality, despite everything,” said Bastian Fink, head of Maneo.

Germany is where the modern idea of homosexuality was born, thanks to pioneering Weimar-era researcher Magnus Hirschfeld. But the road to equality began only half a century ago when Germany – East and West – decriminalised homosexuality, with age of consent equalised only in 1994.

Nazi-era convictions against homosexuals were overturned in 2002, but post-war convictions only in 2016. Last year, the Bundestag voted in favour of marriage equality but, unlike the lengthy Irish debate and referendum, Germany’s parliamentary vote came out of nowhere: triggered by a throwaway remark by chancellor Angela Merkel, who herself voted against it.

The progressive cultural shift is visible in Berlin’s police force, once an enemy of the gay community, now with dedicated community outreach workers. Last year, Berlin police registered 164 cases of hate crimes with homo- or transsexual victims, the same number as the previous year.

“These numbers don’t mean we are Europe’s capital of homophobia or transphobia,” warned Anne Griesbach-Baerns, police commissioner for LGBTI affairs. “It means people are daring to come forward. But as we step up our community contact we expect those figures to rise further.”

Shifting mood

A heated subject of debate is the threat to the gay community, real or perceived, from conservative Turkish and Arab men, and criminal gangs from Romania and Bulgaria.

The culture clash is particularly obvious in multicultural neighbourhoods like Neukölln, where groups of Arab-speaking men sit outside shisha bars across the road from gay bars. “The mood has got worse in the last two years,” said Maurus Knowles, a gay bar owner here who has been attacked himself and fears the mood is “beginning to tip”.

Some point to the 2015-2016 arrival of more than one million migrants – many raised in homophobic cultures in Afghanistan, Syria and northern Africa – and a 12 per cent rise in hate crimes against homosexuals in the same period.

But German police warn against oversimplification, saying by far the largest group behind homophobic attacks are German men under 30.

Back at the Maneo centre, 28 years in business, manager Bastian Fink warns of viewing Berlin as a gay El Dorado.

“Even in liberal Berlin people ask themselves on the street, ‘Do I hold my boyfriend’s hand or not?’” he said. “As long as people still have to adapt their behaviour to their surroundings it’s disastrous for us all.”