He asked for an autograph for one of the women he was with and Bieber let fly with a vicious right hook.
'The autograph wasn't even for me - I respect his professionalism but I've never been a fan,' said Richmond.
However the simple request upset the singer. 'He seemed to be in one of those "I don't want to sign autograph" phases. He was all "Get out of my face."
'He didn't connect. I'm pretty good at ducking punches.'
Richmond grabbed the three-time-Grammy nominee and hurled him to the floor before any of the singer's posse could intervene.
'I wasn't trying to hurt anyone,' he said. 'I wasn't trying to get arrested. Any man would do what I did because he showed such disrespect,' Richmond said.
'I asked him: "What are you doing? They only wanted an autograph. Don't be so disrespectful."'
Neither man was hurt in the brawl. The following day, Bieber, 22, posted a black-and-white selfie, captioned: 'Not a scratch on this pretty boy.'
But while the fight was over in seconds, the aftermath has lingered.