++++ 1.Community law - Principles - Rights of the defence - Observance thereof in the context of administrative proceedings ( Regulation No 17 of the Council, Art . 14 ) 2.Community law - Principles - Fundamental rights - Right of natural persons to the inviolability of their homes - Not applicable to undertakings - Protection against arbitrary or disproportionate intervention by the public authorities ( Regulation No 17 of the Council, Art . 14 ) 3.Competition - Administrative procedure - Commission' s powers of investigation - Scope - Access to undertakings' premises - Limits - Specification of the subject-matter and purpose of the investigation ( Regulation No 17 of the Council, Art . 14 ) 4.Competition - Administrative procedure - Commission' s powers of investigation - Limits - Situations requiring the assistance of the national authorities ( Regulation No 17 of the Council, Art . 14 ) 5.Competition - Administrative procedure - Commission' s powers of investigation - Assistance of the national authorities - Procedural rules laid down by national law - Review by national courts - Limits ( Regulation No 17 of the Council, Art . 14(6 ) ) 6.Measures adopted by the institutions - Statement of reasons - Obligation - Scope - Decision ordering an investigation under Article 14(3 ) of Regulation No 17 ( Regulation No 17 of the Council, Art . 14(3 ) ) 7.Competition - Administrative procedure - Decision ordering an investigation - Adoption on the basis of delegated powers - Legality - Consequences - Imposition of fines for non-compliance ( Merger Treaty, Art . 17; Regulation No 17 of the Council, Arts 14(3 ) and 15 ) 8.Competition - Administrative procedure - Decision imposing a periodic penalty payment on an undertaking - Hearing of the undertaking concerned and consultation of the Advisory Committee - Must take place before the definitive amount of the periodic penalty payment is fixed ( Regulation No 17 of the Council, Art . 15 ) 9.Measures adopted by the institutions - Presumption of validity - Consequences