Absolutely no problem whatsoever as long as it's in checked luggage. For flights within Europe you can now take Swiss Army style knives even on board. They came to their senses.

Nothing to declare, either.

The only thing you might get into trouble for is if the knife is a valuable antiquity and you intend to sell it in Zurich, or it is made out of a material that is not allowed (protected species). Since those unlikely scenarios are probably not the case, just bring the darn thing and enjoy it.

Till