Case C-712/17: Judgment of the Court (First Chamber) of 8 May 2019 (request for a preliminary ruling from the Commissione tributaria regionale di Lombardia — Italy) — EN.SA. Srl v Agenzia delle Entrate — Direzione Regionale Lombardia Ufficio Contenzioso (Reference for a preliminary ruling — Value added tax (VAT) — Fictitious transactions — Impossibility of deducting the tax — Obligation on the issuer of an invoice to pay the VAT indicated thereon — Fine in an amount equal to the amount of the improperly deducted VAT — Whether compatible with the principles of VAT neutrality and proportionality)