You can buy it at Migros Garden Do-It_yourself Centre.  It comes in a small bottle, and has a picture of a living room (sofa, lamp, wall). It's found in the craft paints  section rather than the actual paint section, but this is what the guy in the paint section gave to me when I asked. 

Good luck!

If you have lived there a while, you will find that the paint colour has settled. So not as white as what you buy. Additionally, dont always go for the cheapest brand. It is too watered down and covers less. I have had to paint a few whole walls in my last move. Its worthwhile, to prevent losing your deposit.

There is a shop called Quincaillerie Baud in Eaux Vives, which is bound to be able to help. They are one of those wonderfully quirky hardware shops where you just know you will find just what you are after, however obscure it might be.

They are in Rue des Photographes 7.

Just did a websearch on them, and am pleased to be able to recommend a business that has been around since 1841!

Thank you to all 3 for the helpful posts - i am going to go check it out tomorrow!