There is a small antiques market in Fiesole on the first Sunday of the month now through July. At Piazza Mino da Fiesole, from 8:00 am to sunset. Mercato del Piccolo Antiquariato a Fiesole 2007. Phone 800 414 240 or visit www.comune.fi.it (though I couldn't find any more info except the dates in the caledar they have).
