The French-language blog sooshi has pictures of Uchitomi, a Japanese grocery with stores in Genève and Lausanne. The selection looks very nice!
I have also spotted real yuzu recently at the Bürkliplatz market in Zürich. In the summer I have seen live shiso plants there, both red and green too, Japanese-style sweet potatoes at Barkat, and satoimo (taro roots) at the Indian grocery store next the Hooter's at Helvetiaplatz. It's really great to see more 'exotic' Japanese and Asian produce more easily available here. When I first came to visit Switzerland back in the mid-'90s, you had to buy fresh ginger in the exotic food department at Globus! How times have changed. .