Can the Tax Office add a penalty on top of the assessment?
Yes — filing penalty on omission, fault penalty on intent/gross negligence. Both: objection possible + mitigation on personal circumstances.
Two penalty types in tax law: (1) Filing penalty (AWR art. 67a-67e) — on omission/late filing or payment, fixed amount (€131-€5,514). Objection possible; mitigation on extenuating circumstances. (2) Fault penalty (AWR art. 67d-67f) — for intent (25-100% of the tax) or gross negligence (25-50%). The Tax Office must PROVE INTENT — "I didn't know" is a valid defense if you acted diligently. ECHR art. 6 (fair trial) applies to fault penalties — therefore right to be heard during objection. Mitigation possible on limited income, serious illness, or errors discovered after the assessment. Object within 6 weeks, list grounds explicitly.