Case C-787/19: Judgment of the Court (Sixth Chamber) of 27 January 2021 — European Commission v Republic of Austria (Failure of a Member State to fulfil obligations — Taxation — Value added tax (VAT) — Directive 2006/112/EC — Articles 306 to 310 — Special scheme for travel agents — Application to all types of clients — National legislation excluding travel services that are provided to taxable persons who use those services for their business — Article 73 — Taxable amount — Determination of a taxable amount on a flat-rate basis for groups of services or for all services provided during the taxable period — Incompatibility)