Where can I find plain simple ones in Zurich without any ornamental designs on them? Coop DIY don't stock them. Something in this direction or even more simpler looking would be ideal.

You might not find them any longer, due to their non resistance to fire.

That is the impression I am getting so far too. They are available in Germany and UK but I have not seen them anywhere in Zurich so far.

We are changing flats and in the living room the Styrofoam ceiling tiles are coming off. If we get the landlord to fix it and paint the apartment then the rent would go up by around CHF200 per month. As we might be here for rest of our life I don't fancy paying 200 more every month when I could do it myself.

The other option is I could just remove them and have clean painted ceiling.

So no simple Styropor Deckenplatten available in Zurich?

Probably the most extensive selction of DIY is Hornbach, and as a german parent company, they stock a lot of german goods. I have purchased styrofoam pieces for decoration around ceilings and floors, but have no idea if they have those ceiling plates you mention. Might be worth a visit though. They have a store around Zurich. www.hornbach.ch