Article 21
Where a Member State ascertains that a product declared to be in conformity with the terms of this Directive does not comply with Articles 2 and 3, it shall take all appropriate measures to withdraw those products from the market, prohibit the placing thereof on the market or restrict free movement thereof.
The Member State concerned shall immediately inform the Commission of any such measure, indicating the reasons for its decision, and in particular whether non-conformity is due to:
(a) failure to comply with Articles 2 and 3, where the product does not meet the technical specifications referred to in Article 4;
(b) incorrect application of the technical specifications referred to in Article 4;
(c) shortcomings in the technical specifications referred to in Article 4 themselves.

The Commission shall carry out a consultation of the parties concerned as soon as possible. Where the Commission finds, after this consultation, that the action is justified, it shall immediately so inform the Member State that took the action as well as the other Member States.

Where the decision referred to in paragraph 1 is attributed to shortcomings in the standards or technical specifications, the Commission, after consulting the parties concerned, shall bring the matter before the committee referred to in Article 19, as well as the committee set up under Directive 83/189/EEC in the case of shortcomings in a harmonized standard. within two months if the Member State which has taken the measures intends to uphold them and shall start the procedures referred to in Article 5 (2) .

The Member State concerned shall take appropriate action against whomsoever made the declaration of conformity and shall inform the Commission and the other Member States thereof.

The Commission shall ensure that the Member States are kept informed of the progress and outcome of this procedure.