"Sorry to show you this. It's the face of homophobia," wrote Wilfred de Bruijn on his Facebook page.

The accompanying photograph shows De Bruijn with two black eyes, skin covered in cuts and bruises, and a bloodstained shirt – the results of a vicious attack on him and his boyfriend on Sunday.

Gay rights organisations in France fear homosexuals are being targeted as part of a wave of violent protests against the Socialist government's "marriage for all" bill.

In another area of Paris on Saturday evening police confirmed a similar attack on a man walking with his partner, while the same night a LGBT centre was covered in anti-gay marriage posters.

De Bruijn also described the attack on Facebook: "Last night, in the 19th arrondissement of Paris, Olivier and I were badly beaten up just for walking arm in arm. I woke up in an ambulance covered in blood, missing tooth and broken bones around the eye. I'm home now. Very sad. Olivier takes care of me. Forbidden to work for at least 10 days."

De Bruijn, a Dutchman who has lived in the French capital since 2003, said he remembered nothing, but Olivier told French journalists he and his partner had been attacked at about 3.25am.

"We were leaving a dinner washed down with plenty of wine with friends. We were walking arm in arm towards the Ourcq metro. Not in a 'homo' style. We'd had a lovely evening and we were talking about it. A bit loudly, perhaps, he said.

Backlash – French president François Hollande. Photograph: Robert Pratta/Reuters

"Then I heard: 'Ah, homosexuals!' I took the first hit in the eyes. I tried to protect myself but I received six hits. It was a wave of hatred. Very violent. I saw my partner on the ground where his head had become a football. I shouted 'Get lost!' and they ran off."

Olivier told the Rue89 news website the police had suggested it might have been wiser for them to have taken a taxi at that time of night, which had enraged him further. The pair have filed a legal complaint for aggression.

Bertrand Delanoë, the city's mayor, issued a statement saying he was "angry and sad at the brutal homophobic aggression". He said: "The unleashing of violence this couple suffered for the sole reason that they were holding hands is profoundly worrying and absolutely unspeakable."

The gay rights group SOS Homophobie said it had received 60 complaints of anti-gay hatred in Paris in the past week. It blamed opponents of President François Hollande's gay marriage bill, who organised several large-scale and noisy protests in recent months.

An anti-homophobia demonstration has been arranged for Wednesday night in the Marais area of Paris.

De Bruijn said he had hesitated a long time before publishing his photograph on Facebook, but said he and Olivier had decided they had to take a stand.

"We did it so it would be seen and known, and it worked. But it's an aggression like many others. What matters is the larger question of homophobia in France today," De Bruijn said.