What is PACS?
Anyway, I think it depends on the kanton; I know in my kanton my registered partnership (different sex) is useless for permits, taxes and most other official situations. Sometimes though, it affects how they treat you but usually only if you have kids.
But again, Geneva might be different, but the impression I have is that registered partnerships are only relevant to same sex couples because the government figures the others have no reason not to marry

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