Key legal question
Whether the constitutional complaint against the Graubünden tax assessment and the Zurich assessment proposal was admissible in the double taxation context.
Extracted holding
The complaint was inadmissible because the challenged Zurich act was only a non-binding assessment proposal and therefore not an appealable sovereign act.
Extracted reasoning
A double-taxation complaint must be filed no later than when the second conflicting tax claim is asserted, but here the complaint was directed only against the final Graubünden assessment while attacking merely a proposal from Zurich that had no legal effect and did not yet fix the tax factors.