Soap bubbles in the sunshine, outside the Hôtel de Ville.  Blowing, or rather throwing bubbles, using a string between two sticks and a bucket of soap mixture, is a silent form of busking (aimed mostly at passing children and their parents).  You might not like the repertoire of a musical busker, especially if they’re over amplified or sing out of tune, but it’s hard to imagine anyone objecting to soap bubbles.  That said, I love the sound of live music in the street and guess you could tire of bubbles.