I stood in front of him, pointed the camera and pressed the button!
It was about 15 years ago. Near Sacré-Coeur, the streets were full of noisy wastes of space, singing badly to overly loud music from their CD players and calling it "busking". This chap was different. He had a ball; he climbed the lamp post and hung there; as I remember, he took off his T-shirt while hanging, all the time balancing the ball. It was hugely impressive. I was transfixed and put a generous amount in the cap on the ground.
I was shooting against the light, I knew very much less about photography than I know now, and he ended up rather under-exposed. Only recently, with the advent of high-quality noise reduction software, have I found it possible to process the shots into something usable. I wish I'd taken more!
Jeremy