1 . ACTION FOR FAILURE OF A STATE TO FULFIL ITS OBLIGATIONS UNDER THE TREATY - STAGE PRECEDING COMMENCEMENT OF PROCEEDINGS - REASONED OPINION - EFFECT RESTRICTED TO COMMENCEMENT OF PROCEEDINGS BEFORE COURT - EXEMPTION OF MEMBER STATE FROM COMPLIANCE WITH ITS OBLIGATIONS - NOT PERMISSIBLE ( EEC TREATY , ART . 169 ) 2 . TAX PROVISIONS - INTERNAL TAXATION - SYSTEM OF DIFFERENTIAL TAXATION OF A DISCRIMINATORY NATURE - GRANT OF TAX ADVANTAGES SUBJECT TO CONDITIONS WHICH CAN BE SATISFIED ONLY BY DOMESTIC PRODUCTS - PROHIBITION ( EEC TREATY , ART . 95 ) 3 . TAX PROVISIONS - INTERNAL TAXATION - RULE AGAINST DISCRIMINATION - DIRECT EFFECT - DATE ON WHICH RULE TOOK EFFECT ( EEC TREATY , ART . 95 ) 4 . AIDS GRANTED BY MEMBER STATES - AID IN FORM OF TAX DISCRIMINATION - AUTHORIZATION - NOT PERMISSIBLE ( EEC TREATY , ARTS 92 , 93 AND 95 ) 5 . COMMUNITY LAW - DIRECT EFFECT - NATIONAL TAXES INCOMPATIBLE WITH COMMUNITY LAW - REFUND - DETAILED RULES - APPLICATION OF NATIONAL LAW - TAKING INTO ACCOUNT OF ANY PASSING-ON OF TAX - WHETHER PERMISSIBLE