Judgment of the Court (Ninth Chamber) of 15 April 2021.#Grupa Warzywna Sp. z o.o. v Dyrektor Izby Administracji Skarbowej we Wrocławiu.#Request for a preliminary ruling from the Wojewódzki Sąd Administracyjny we Wrocławiu.#Reference for a preliminary ruling – Common system of value added tax (VAT) – Directive 2006/112/EC – Article 273 – Overstatement in the tax return of the amount of the refund of VAT – Error of assessment by the taxable person concerning the taxable nature of a transaction – Correction of the tax return following an audit – Penalty of an amount equal to 20% of the overstated VAT reimbursement – Principle of proportionality.#Case C-935/19.