Beginning in mid-August, there will be fleamarket days in the various Kreise of Zurich, the Krisflohmi. Seven Kreise participate, and each has its designated day where everyone can just set up a stand in front of the house.
For further info and to sign up (if you sign up, your stand will be marked on a map so that it is easier to find):
http://kreisflohmi.ch/?fbclid=IwAR0e...hV1xrJD3nYZnCw