Michel Baldy, now an apartment block caretaker, took Banier to court after he wrongly accused Baldy of homophobia.
The pair first met last year, when Baldy was homeless and living on the Champs Elysée in Paris.
Banier - also a novelist, artist and actor, and a friend of luminaries including Pablo Picasso, François Mitterand, Kate Moss and Princess Caroline of Monaco - took a photo of Baldy without his permission. When he was asked to delete the photo, he reportedly said “shut your face, bum,” and took a swipe at the homeless man.
The photographer then reported Baldy to the police for homophobia and violence – at the hearing Baldy was acquitted of accusations of homophobia, and decided to sue for slander.
Baldy has since spoken of how he has never forgiven Banier for the humiliation caused after the accusation.
“I was already living on the streets, but with this it was like I didn’t exist at all. I was shattered,” said Baldy to radio station RTL.
“I hope that with this court case, Banier rectifies what he has done, and that he says that I never threatened him and I’m not homophobic.
“It’s clear he didn’t behave how he should have. For a photographer, it’s clear.”
Banier has previously been in the limelight for his relationship with L'Oréal heiress Liliane Bettencourt, who made him the sole beneficiary of her will, before later removing him.