TREATY ESTABLISHING THE EUROPEAN ECONOMIC COMMUNITY, PART TWO - FOUNDATIONS OF THE COMMUNITY, TITLE I - FREE MOVEMENT OF GOODS, CHAPTER 1: THE CUSTOMS UNION, SECTION 1: ELIMINATION OF CUSTOMS DUTIES BETWEEN MEMBER STATES, ARTICLE 12
++++ ARTICLE 12 MEMBER STATES SHALL REFRAIN FROM INTRODUCING BETWEEN THEMSELVES ANY NEW CUSTOMS DUTIES ON IMPORTS OR EXPORTS OR ANY CHARGES HAVING EQUIVALENT EFFECT , AND FROM INCREASING THOSE WHICH THEY ALREADY APPLY IN THEIR TRADE WITH EACH OTHER .