Case C-253/09: Judgment of the Court (First Chamber) of 1 December 2011 — Commission v Republic of Hungary (Failure of a Member State to fulfil obligations — Freedom of movement for persons — Freedom of establishment — Purchase of property for use as a new principal residence — Establishing the basis of assessment for the tax levied on the purchase of real property — Deduction of the value of the residence sold from the value of the residence purchased — Exclusion of that deduction if the property sold is not situated within the national territory)