dear all,
do you have any idea about an open chochate factory on Sundays ,,,[/I]

Not in Zurich....i think.

http://www.zuerich.com/en/Visitor/tours/city-tours.html

A quick search brought up an old thread, perhaps you can reach them for possible tours on a Sunday.

Chocolate factory in Zurich?

Ok, not in Zurich, but worth the drive is Nestle's Maison Cailler in Broc. Really fun tour (Disneylandish) and great chocolate at the end! Open until 5 on Sundays.

I did this tour. It is pretty good....