THere might be special paint stores, but one can buy that in a do-it-yourself.
I am sure you got familiar with Coop: usually, the largest coop stores have a DIY area/specialty shop. You can find more details on the coop website. http://www.coop.ch/en/index-en.htm
. THere are also other kind of stores, mostly superstores out of the cities, carrying DIY equipment.
On the other hand, make sure you can repaint your apartment/house! Usually, here the apartment is cleaned out by the previous tenant, and if there are wall papers painting over them (even painting clean over a filthy wall paper) is considered a depreciation, and you may end up paying for the new job being done when you leave!!!