The Directive is based on the principle of full harmonisation. This means that Member States can no longer implement or apply either less or more restrictive or prescriptive consumer protection measures in the area it harmonises. As the Preamble to the Directive explains, in order to remove internal market barriers caused by regulatory disparities and to increase legal certainty for both consumers and businesses, it was necessary to replace existing national systems with a uniform regulatory framework at Community level (see in particular Recitals 5, 12 and 13).
The full harmonisation effects of the Directive have been spelled out in the "Total Belgium" case. The Court of Justice, while examining the compatibility of a Belgian law prohibition on combined offers with the Directive's provisions, held that "the Directive fully harmonises those rules at the Community level. Accordingly, [...] Member States may not adopt stricter rules than those provided for in the Directive, even in order to achieve a higher level of consumer protection". Thus, the Directive was found to preclude a national prohibition of combined offers.
There are currently two types of limitations to the full harmonisation effect of the Directive. First, according to Article 3(9), "in relation to 'financial services' [...] and immovable property, Member States may impose requirements which are more restrictive or prescriptive than this Directive in the field which it approximates". Thus, minimum harmonisation applies to these two sectors. As Recital 9 explains, "financial services and immovable property, by reason of their complexity and inherent serious risks, necessitate detailed requirements, including positive obligations on traders". Consequently, in these sectors, Member States can impose rules which go beyond the provisions of the Directive, as long as they comply with EU law (e.g., in the field of payment services, Directive 2007/64/EC establishes fully harmonised rules).
Second, a temporary derogation from the full harmonisation principle applies to national provisions which implement directives containing minimum harmonisation clauses. According to Article 3(5), for a period of six years from 12 June 2007, Member States shall be able to continue to apply more restrictive or prescriptive national provisions. Thus, Member States may apply existing rules which had been established pursuant to the minimum harmonisation clauses contained in, for example, Directive 98/6/EC on the indication of prices of products offered to consumers or Directive 97/7/EC on distance contracts. However, such measures must be essential and proportionate in attaining the objective of consumer protection envisaged in those measures.
Both limitations will be subject to the Directive's review to be carried out by 12 June 2011 (see Article 18).
 Joined Cases C-261/07 and C-299/07 VTB-VAB NV v Total Belgium, and Galatea BVBA v Sanoma Magazines Belgium NV, not yet reported.
See also the Opinion of Advocate General Trstenjak, of 3 September 2009, in Case C-304/08 Zentrale zur Bekampfung unlauteren Wettbewerbs e.V. v Plus Warenhandelsgesellschaft mbH, pending. Also relevant is Case C-540/08 Mediaprint Zeitungs- und Zeitschriftenverlag GmbH & Co KG v 'Osterreich'-Zeitungsverlag GmbH, pending.
 OJ L 80, 18.3.1998, p. 27-31.
 OJ L 144, 4.6.1997, p. 19-27.