Well, here in Switzerland, it is.

Whether you are practicing or not doesn't play a role. I guess 95% of all church tax payers don't practice (including me).

Which means that you either went through the official de-registering process or you did not state your religious status correctly when immigrating into Switzerland. By definition, you cannot be catholic without being member of the catholic church.

Frank,

I had this discussion with Einwohnerkontrolle when we first registered here. According to the helpful folks I spoke to, the events of one's childhood, or even of one's past religious practice do not determine one's current religious affiliation. As the nice lady explained to me, if you are not a practicing Catholic, if you do not intend to practice Catholicism while in Switzerland, you do not need to register as Catholic, you are not required to pay church tax.

If, however, during your stay in Switzerland you decide that you do wish to become active again in the faith, then you need to pony up. In Switzerland, you've gotta pay to pray.

Of course one can be catholic without being a member of the (a) Church. You can even remain Catholic without taking membership in a Swiss Kirchgemeinde. But as I said earlier, that is a matter of one's own conscience.

For Roman Catholics in Zurich the following applies:

If you are are "member" of the Roman Catholic Church according to canonical law (being baptized is enough) and happen to settle down in Zurich, according to cantonal law you automatically become a member of the Kirchgemeinde (loosely translated as the recognized parish area/association). The only way out is to declare that you want to leave the church in writing. This has to be sent to your Kirchgemeinde.

You can find out which one it is under:
http://www.kirche-zh.ch/
Has a search function where you type in your address.

For those interested in learning more on this "fascinating" topic (in German only):
http://www.zh.kath.ch/publikationen/.../austritte.pdf

And for any relaxed Catholic who's married in a civil ceremony, divorced or married to someone who is divorced, you're a sinner and effectively excommunicated. At least you can't receive the sacraments. So therefore, not catholic either.

Holy dogma, Batman! You are right; I stand corrected.

However, I'm sticking to the advise I was given from Einwohnerkontrolle, since I left the institutional Church (in my heart, as in my home country there is no such thing as registrering/deregistering one's religion) long before coming to Switzerland.

(As for the non-institutional church... well, can't hurt to keep that door cracked the tiniest fraction open... but I promise never to cross the threshold of a Swiss church. )

Dona nobis pacem.

I think this is open to debate since it is as you rightly mentioned Canon Law; with so many italian, spanish and portuguese immigrants and their second/third etc. generation offspring, i'm wondering whether the Catholic Church in Switzerland really ever bothered to enforce this Law, and am also wondering how they could actually to so; moreover not registering or de-regestering as a church member would it really be considered tax avoidance (certainly not tax evasion)?
i'm wondering whether the reference to Catholics settling in Zurich applies only to the Confœderatio Helvetica and not to all Catholics 'happening' to be in Zurich.
I have not read the .pdf since i can't read German, so perhaps you can shed some light Mica.
A friend of mine a portuguese first generation immigrant to Switzerland clearly said to me "I'm Catholic, but not for the Swiss" and then he laughed, do i blame him? or condone him? mmmmhhhh...