Whilst some problems were being resolved through the harmonisation of legislations, the Member States, tempted by protectionism, in particular during the gloomy economic climate of the 1970s, were adopting new legislation and creating further technical obstacles to trade. The European institutions' laborious work to remove those obstacles therefore resembled the endless tasks of the Danaides, punished by Greek gods to carry water eternally in leaky jars. For that reason, the Commission considered a fresh approach to the problem. For that it relied upon the case law of the Court of Justice. In its judgment of 20 February 1979 in the "Cassis de Dijon" case (concerning the sale in Germany of blackcurrant liqueur produced in France), the Court of Justice gave a very broad definition of the obstacles to free trade which were prohibited under Article 30 et seq. of the EEC Treaty (Articles 34 to 37 TFEU, ex Art. 28, Art. 29, Art. 30, Art. 31 TEC, see case 120/78]. It stated that any product lawfully manufactured and marketed in a Member State should in principle be admitted to the market of any other Member State.
Even if they are applicable without distinction to domestic and imported products, national regulations may not create obstacles unless they are necessary to satisfy mandatory requirements and are directed towards an objective of general interest which is such as to take precedence over the requirements of the free movement of goods, that is one of the basic rules of the European Union. In plain language, a country must not bar the way to competing products from another Member State solely because they are slightly different from domestic products. If it does so, the Commission will take proceedings against it as far as the Court of Justice, where it stands every chance of being condemned on the basis of existing case law. According to another Court judgment, national provisions must not discriminate against the traders to whom they apply or have the effect of discriminating between the marketing of national products and that of products from other Member States [Case 268/91].
In parallel with the application of the "Cassis de Dijon" principle, the Commission secured, in 1983, the adoption by the Council of a procedure for the provision of information by the Member States on any new technical standards and regulations that they envisage. This procedure was codified in 1998 [Directive 98/34], while its field of application was extended to information society services in the new Member States [Decisions 2004/299 and 2004/330]. Thanks to the information procedure, the Commission is notified by the competent authorities of any new technical standards or regulations that they envisage and can thus notify the other Member States and request amendments before their entry into force. This is an example of shared sovereignty: the Member States have agreed to lose their independence of action in the field of standardisation, but have gained in exchange the right of surveying the actions of their neighbours [see section 1.1.2].
A similar information procedure exists in the framework of the EEA agreement [see section 25.1]. Transparency is thus ensured throughout the European Economic Area. The information procedure has proved to be a vital instrument for preventing the emergence of new obstacles to trade which can result from technical standards or rules. Furthermore, it is a good instrument for the establishment of a technical environment common to all undertakings. The Court of Justice has ruled that technical regulations which have been adopted in violation of the procedure for the provision of information, i.e. without notification, are inapplicable, have no legal effect for individuals and national courts must decline to apply them [Case C-194/94]. Stringent rules and procedures are to be followed by the competent authorities of a Member State when taking or intending to take a decision, which would hinder the free movement of a product lawfully marketed in another Member State [Regulation 764/2008, see section 6.2.3].