RIGHT TIME BOTH AS REGARDS THE ORIGINAL FIXING OF THE TARIFFS AND THEIR SUBSEQUENT AMENDMENT SHOULD THE NEED ARISE .
19 WHEN TRANSPORT TARIFFS ARE FIXED SIMULTANEOUSLY IN THE CURRENCIES OF THE TWO MEMBER STATES CONCERNED , AS THE CASE OF BELGIUM AND FRANCE , AND THERE IS AN ALTERATION IN THE EXCHANGE RATES BETWEEN THEIR CURRENCIES SUCH AS TO AFFECT THE CONDITIONS OF COMPETITION BETWEEN CARRIERS IN A MANNER WHICH IS CONTRARY TO THE AIM OF THE REGULATION , THOSE STATES ARE UNDER AN OBLIGATION TO SEEK A REVISION OF THE TARIFFS IN ACCORDANCE WITH THE PROCEDURE WHICH HAS BEEN DESCRIBED . THAT OBLIGATION IS INHERENT IN THE VERY CONCEPT OF BRACKET TARIFFS WHICH UNDER THE SYSTEM OF REGULATION NO 1174/68 ARE CONCEIVED AS SINGLE TARIFFS , EVEN IF EXPRESSED IN TWO CURRENCIES , AND AS BEING REQUIRED TO HAVE ESSENTIALLY THE SAME SPREAD .
20 THE SCOPE OF THAT OBLIGATION MUST NEVERTHELESS BE UNDERSTOOD IN THE SENSE THAT THERE CANNOT BE AUTOMATIC ADAPTATION OF THE BRACKETS TO THE VARIATIONS IN EXCHANGE RATES IN A SYSTEM OF FLOATING RATES OF EXCHANGE . TO TAKE ACCOUNT OF THE FREQUENT AND GENERALLY SMALL VARIATIONS WHICH CHARACTERIZE SUCH A SYSTEM WOULD MAKE ANY STABILITY IN TRANSPORT RATES IMPOSSIBLE . THE MEMBER STATES MUST THEREFORE BE RECOGNIZED AS HAVING AN APPROPRIATE DISCRETION IN FULFILLING THEIR OBLIGATION UNDER REGULATION NO 1174/68 TO UNDERTAKE REVISIONS INASMUCH AS REVISION IS NOT REQUIRED EXCEPT WHERE THE CONDITIONS OF COMPETITION ARE APPRECIABLY AFFECTED .
21 IT THEREFORE APPEARS THAT REGULATION NO 1174/68 CONTAINS THE NECESSARY PROVISIONS TO ELIMINATE THE EFFECTS OF DISPARITIES BETWEEN CURRENCIES . FOR THAT REASON , IF IT IS CORRECTLY APPLIED BY THE MEMBER STATES CONCERNED , IT IS NOT APT TO CREATE DISTORTIONS OF COMPETITION OR TO CAUSE DISCRIMINATION AGAINST CARRIERS IN THE EVENT OF A PARITY CHANGE IN THE CURRENCIES OF THE STATES CONCERNED WITH A GIVEN TRANSPORT RELATIONSHIP . UNDER THE DISTRIBUTION OF POWERS EFFECTED BY THE REGULATION IT IS FOR THE MEMBER STATES CONCERNED TO TAKE , IN PURSUANCE OF ARTICLE 4 THEREOF , THE NECESSARY STEPS TO BRING ABOUT AN AMENDMENT OF THE TARIFFS WHEN A CHANGE IN THE CONVERSION RATE BETWEEN THEIR CURRENCIES CAUSES DISTORTIONS OF COMPETITION INCOMPATIBLE WITH THE OBJECTIVE OF THE REGULATION .
22 THE VALIDITY OF THE REGULATION CANNOT THEREFORE BE DOUBTED ON THE GROUND THAT IT DOES NOT MAKE IT POSSIBLE FOR THE EFFECTS OF DISPARITIES IN CURRENCIES BETWEEN THE MEMBER STATES TO BE ELIMINATED .
23 IN VIEW OF THAT CONCLUSION IT IS FOR THE NATIONAL COURT TO ASCERTAIN WHETHER , SUBJECT TO THE DISCRETION MENTIONED ABOVE , THE MEMBER STATE CONCERNED HAS SATISFIED THE OBLIGATION TO ADAPT TRANSPORT TARIFFS TO THE VARIATIONS IN EXCHANGE RATES AND TO DRAW THE NECESSARY CONSEQUENCES AS REGARDS THE PROSECUTIONS PENDING BEFORE IT .
Decision on costs
COSTS
24 THE COSTS INCURRED BY THE GOVERNMENT OF THE KINGDOM OF BELGIUM , THE GOVERNMENT OF THE FRENCH REPUBLIC , THE COUNCIL OF THE EUROPEAN COMMUNITIES AND THE COMMISSION OF