Case C-521/19: Judgment of the Court (Third Chamber) of 1 July 2021 (request for a preliminary ruling from the Tribunal Superior de Justicia de Galicia — Spain) — CB v Tribunal Económico-Administrativo Regional de Galicia (Reference for a preliminary ruling — Taxation — Value added tax (VAT) — Directive 2006/112/EC — Tax inspection — Supply of services as an activity of an agent for performing artists — Transactions subject to VAT — Transactions not declared to the tax authority and not invoiced — Fraud — Reconstitution of the taxable amount for income tax purposes — Principle of VAT neutrality — Inclusion of VAT in the reconstituted taxable amount)