actually your belt should match your shoes
Or I could match my belt and shoes to the pants I wear. ie Navy pants are more suited to a black belt and shoes than to brown ones.
In Switzerland is "smart casual" translated to neon colored sneakers anyway.
Unless the letter/email etc confirming the appointment says otherwise, then err on the side of caution and go smart.
It's personal opinion, but for me, I don't see what difference the job is. If you want the job, then make the effort to stand out.
You're going to make a 1st impression one way or the other, so make it a good one. If you're over-dressed, so what, at least you'll be smart.
I'd go with plain and simple suit (black, charcoal, dark grey, navy blue) plain shirt (def top button done up), no whacky ties and socks, dark shoes that are well and truly clean and polished.
Good luck with it.