Questione giuridica chiave
Whether the public law appeal and subsidiary constitutional complaint were admissible.
Decisione estratta
The public law appeal was admissible in principle; the subsidiary constitutional complaint was inadmissible because the ordinary federal appeal route was open.
Motivazione estratta
The dispute concerned public construction law, no exclusion ground applied, and the neighbor had standing due to proximity; where the public law appeal is available, the subsidiary constitutional complaint is excluded.