Question juridique clé
Whether the public-law appeal against the Geneva decision on opposition to taxation was admissible
Solution extraite
The appeal was admissible as a subsidiary constitutional complaint against a final cantonal decision on procedure costs.
Motifs extraits
Cost allocation in cantonal civil procedure is governed by cantonal law; the decision on opposition to taxation was final and last-instance, and Y. had standing because cantonal law grants the successful party a protected interest in costs.