Case C-304/08: Judgment of the Court (First Chamber) of 14 January 2010 (reference for a preliminary ruling from the Bundesgerichtshof — Germany) — Zentrale zur Bekämpfung unlauteren Wettbewerbs eV v Plus Warenhandelsgesellschaft mbH (Directive 2005/29/EC — Unfair commercial practices — National legislation laying down a prohibition in principle of commercial practices which make the participation of consumers in a lottery conditional on the purchase of goods or the use of services)