If you're interested in how Fez's beautiful pottery and tiles are made, head to Ain Nokbi, a district just outside the medina where potters were relocated in 2013 to spare their neighbours the dust and heat of the kilns. At Art Naji (and neighbouring operations, all popular stops on bus tours), free guides will take you through every phase of production, from pot-throwing to painting to the hand-cutting of the pieces for zellige tilework.
Naturally it ends in a shop (no pressure to buy, though); marked prices are quite high to account for guides' commissions, but the quality is excellent, and you can negotiate if you turn up unescorted. You can even commission a mosaic and arrange for it to be shipped home. The centre is east of Bab Fotouh, an easy ride in a petit taxi, or a reasonably interesting walk through the Al Andalous side of the medina, then a newer residential district. You're getting close when you hear the chip of hammers on tile in less-formal zellige workshops along the road.