Under Article 101(1) of the EC Treaty, agreements between undertakings that restrict competition and may affect trade between Member States are prohibited. According to Article 101(2) of the EC Treaty they are void unless they are exempted from the prohibition under certain conditions laid down in Article 101(3) of the EC Treaty.
Source: Glossary of terms used in EU competition policy, Antitrust and control of concentrations, European Commission, 2002