Does the transfer, pursuant to the law, of the ownership of immovable property owned by a municipality to the State Treasury in return for payment of compensation, in the case where, under the rules of national law, that immovable property continues to be managed by the mayor of the municipality, who is simultaneously the representative of the State Treasury and the executive body of the municipality, constitute a taxable transaction within the meaning of Article 14(2)(a) of Council Directive 2006/112/EC?