For touchup jobs hit ebay or something and search with the brand and colour code. For example BMW Titansilber, or Lexus 8P8, or if you're really fancy go with something like Glasurit FER 300/12.
But if you want to repaint your Ferrari you should not ask around in forums for cans of paint
For Zurich, try the Farbshop near Kreuzplatz in Forchstrasse 37. http://farbhof-forchstrasse.ch/autolacke/
They say they mix paint, and I've been there last week to get some detailing supplies (sandpaper) and the lady is very kind and helpful.