CELEX: 62001CC0147
Language: en
Date: 2003-03-20 00:00:00
Title: Opinion of Mr Advocate General Jacobs delivered on 20 March 2003. # Weber's Wine World Handels-GmbH and Others v Abgabenberufungskommission Wien. # Reference for a preliminary ruling: Verwaltungsgerichtshof - Austria. # Indirect taxation - Duty on sales of alcoholic beverages - Incompatibility with Community law - Recovery of duty. # Case C-147/01.

OPINION OF ADVOCATE GENERAL JACOBS delivered on  20 March 2003(1)
         Case C-147/01  Weber's Wine World and Othersv Abgabenberufungskommission Wien 
            (())
            
      
         
      1.  On 9 March 2000, in response to questions from the Austrian Verwaltungsgerichtshof (Administrative Court), the Court of Justice
      ruled in the  
       EKW  case  
      
         			(2)
         		 that Article 3(2) of Council Directive 91/12/EEC  
      
         			(3)
         		 precluded the maintenance of certain local and regional beverage taxes in Austria, in so far as they applied to alcoholic
      beverages.  However, it limited the effect of that ruling, as regards claims for reimbursement of tax paid or chargeable before
      the date of the judgment, to claimants who had already initiated legal proceedings or raised an equivalent administrative
      claim.
      
      2.  A week before the judgment, the Wiener Landtag (Vienna regional legislature) had amended the rules governing reimbursement
      of tax credits.  Under that amendment, which applied also to situations which had arisen before its promulgation, tax wrongfully
      levied could no longer be recovered by the taxable person if the economic burden of the tax had been borne by a third party.
      
      3.  The Verwaltungsgerichtshof now wishes to know whether it is compatible with the  
       EKW  ruling, and with Austria̕s duty of cooperation under Article 10 EC, to apply such an amendment to claims raised before the
      date of that judgment. 
       Background and proceedings
      
      4.  Until 2000,  
      
         			(4)
         		 various taxes, all apparently comparable in their effects and domestic legal basis, were levied on retail sales of ice cream
      and beverages by regional and municipal authorities in Austria.  They provided a significant proportion of those authorities̕
      resources.  It appears that (at least in Vienna where the taxes with which the present case is concerned were levied) they
      were self-assessed:  traders calculated the amount as a percentage of their taxable sales and declared it to the authorities.
      
      5.  In 1997, following objections by traders casting doubt on the compatibility of those taxes with Community law – specifically
      with the VAT rules, the excise duty directive and the rules on State aid – the Verwaltungsgerichtshof sought guidance from
      the Court on that aspect in  
       EKW , which concerned a hospital cafeteria in Vienna and a wine trader in a municipality in Upper Austria.
      
      6.  On 1 July 1999, Advocate General Saggio delivered his Opinion in that case, concluding that the Court should find the tax
      incompatible with the excise duty directive and the State aid rules.
      
      7.  He also examined the Austrian Government̕s request for a limitation of the temporal effects of the judgment in the event of
      a finding of incompatibility, but reached the view that there were no exceptional circumstances justifying such a limitation.
      
      8.  At paragraphs 66 to 68 of his Opinion, he dealt with the argument that to allow claims for reimbursement of tax wrongly levied
      in the past would unjustly enrich traders who had in fact passed the tax on to consumers.  In that regard, he pointed out
      that (in accordance with the case-law) in order to resist claims for reimbursement the authorities would have to prove that
      the burden of the tax had indeed been transferred to consumers.  However, not only would such proof be difficult to provide,
      but it might well be the case that traders had not in fact passed on the burden of the tax and had been obliged to assume
      it themselves.  
      
         			(5)
         		
      9.  The Advocate General̕s Opinion gave rise to considerable concern that very large sums would have to be reimbursed, seriously
      compromising local and regional finances.  Before the Court, the Austrian Government had asserted that ATS 22 000 million,
      equivalent to some 0.9% of gross national product, would be due for repayment for the years 1995 to 1998.
      
      10.  According to the order for reference in the present case, all the Austrian  
       Länder  amended their regional tax codes so that tax wrongfully levied need no longer be reimbursed or set off where the burden had
      been passed on to another person.  In all cases those amendments were made after the delivery of the Opinion in  
       EKW   – and in all cases but one before the delivery of the judgment, but at a time when the date for the latter had been announced.
      
      11.  Under Paragraph 162 of the Wiener Abgabenordnung (Vienna tax code), tax credits must first be set off against tax debts, then
      any surplus must be reimbursed.  Until 2 March 2000, Paragraph 185 read as follows:‘(1) The taxable person may apply for the repayment of credits (Paragraph 162(2)).  Repayment may also take place of the authority̕s
      own motion. 
      (2) Liabilities to duty whose amount has been determined, and which the taxable person will have to pay not later than three months
      from the making of the application for repayment, may be set off against the amount of repayment.̕ 
      
      
      
      12.  On 2 March 2000, the following subparagraphs were added by Article I of amending Law 9/2000:‘(3) No entitlement to repayment exists where the economic burden of the duty has been borne by someone other than the taxable
      person. Where a duty which has thus been passed on has not yet been paid, the tax authority must require payment by a separate
      decision. 
      
      (4) Subparagraph 3 is not applicable to taxable persons who are entitled to benefit from  Anlaßfallwirkung in respect of a tax
      provision which has been held by the Verfassungsgerichtshof [Constitutional Court] to be unlawful.̕ 
      
      13.  The concept of  
       Anlaßfallwirkung  relates to the fact that in Austria a law which is declared unconstitutional by the Verfassungsgerichtshof is not immediately
      or retroactively annulled but remains in force (for a maximum period  laid down by that court) pending the enactment of new
      rules.  Essentially, only those who brought proceedings to challenge it (the proceedings giving rise to the declaration of
      unconstitutionality – the  
       Anlaßfall  – or other proceedings having the same object and pending before the same court at the time of judgment) may benefit directly
      and immediately from the finding of unconstitutionality, unless the Verfassungsgerichtshof decides otherwise.
      
      14.  Subsequently, on 20 February 2001, the phrase ‘nor does the reduction of the determination of duty by self-assessment or an
      assessment decision result in a credit in this respect̕ was added to the end of the first sentence of subparagraph 3.
      
      15.  Article II of the amending Law stated:
       ‘Article I is applicable also to tax liabilities which arose before promulgation of this Law.̕
      
      16.  The explanatory memorandum to the draft amending Law presented to the Vienna regional legislature for adoption referred to
      Advocate General Saggio̕s Opinion in  
       EKW  and pointed out that, if the Court were to follow his view, refunds amounting to some ATS 3 800 million might be claimed
      in Vienna.  Consideration of that possibility had drawn attention to the fact, of general relevance, that the tax code as
      then worded could allow the unjust enrichment of a taxpayer who had incorporated the amount of an indirect tax in the price
      of his supplies, by allowing him to recover that amount when the burden of it had in fact been borne by consumers.  The proposed
      Article I was intended to deal with that general problem, and not specifically with the possibility that very large sums of
      beverage tax might have to be reimbursed.
      
      17.  The explanatory memorandum made no mention of the retroactive effect proposed in Article II.
      
      18.  The draft Law was given a first reading in the regional legislature on 16 December 1999, when it was strongly criticised by
      several opposition members who described it as an attempt to circumvent Community law and in itself undoubtedly contrary to
      that law.  The retroactive effect was also criticised, as was the absence of any clear statement that the burden of proof
      must lie with the authorities since,  
       inter alia , the burden of the tax could not be presumed to have been passed on to customers, and traders could not have been expected
      to provide themselves with evidence that in fact it had not.  It was further asserted that the lawfulness of the tax had been
      questioned as from Austria̕s joining the European Union in 1995.
      
      19.  One week after the final adoption of the amendment to the Vienna tax code, the Court of Justice gave judgment in  
       EKW .  As stated above, it found a tax such as that in issue to be incompatible with Article 3(2) of the excise duty directive,
      but limited the retrospective effect of the ruling to claims – legal proceedings or ‘equivalent administrative claims̕ – raised
      before the date of the judgment.  That limitation was based, according to paragraph 58 of the judgment, on the facts that
      (i) Article 3(2) had not previously been interpreted by the Court and (ii) the Commission̕s conduct might have led the Austrian
      Government reasonably to believe that the tax was in conformity with Community law.
      
      20.  It appears that a large number of claims had in fact been raised, in one form or another, before the date of the judgment
      in  
       EKW  (when the Court had been informed of a total which might have to be reimbursed if all claims were to succeed, but not of
      the number of claims estimated to have been brought already).  In its observations in the present case, the Austrian Government
      states that 16 000 such claims, representing some ATS 3 000 million, are pending for Vienna alone, and suggests that their
      number is due at least in part to the fact that the Verwaltungsgerichtshof has decided that the concept of ‘equivalent administrative
      claims̕, used by the Court in the  
       EKW  judgment, must be given a broad interpretation.
      
      21.  At least some of those claims have been refused by the tax authorities in Vienna, and at least four of those refusals have
      been challenged on appeal before the Verwaltungsgerichtshof.  They concern two restaurants, a  
       Gasthaus  and a wine merchant.  It may be assumed that those four cases, which have given rise to the present request for a preliminary
      ruling, are test cases the result of which will determine the fate of a very large number of other claims not only in Vienna
      but throughout Austria.  
      
         			(6)
         		  It appears that the taxes in issue here were initially self-assessed and paid, and that the claimants then withdrew their
      original assessments and claimed reimbursement.
      
      22.  The Verwaltungsgerichtshof has decided to stay the proceedings in those appeals and seek a preliminary ruling on the following
      question:‘Do Article 10 EC (formerly Article 5 of the EC Treaty) and point 3 of the operative part of [the  
       EKW  judgment], according to which Article 3(2) of Directive 92/12/EEC may not be relied on in support of claims relating to a
      tax such as the duty on alcoholic beverages paid or chargeable prior to the date of that judgment, except by claimants who
      before that date initiated legal proceedings or raised an equivalent administrative claim, preclude the application of the
      provision, created by the amendment to the Wiener Abgabenordnung (Vienna Tax Code, WAO) of 2 March 2000, LGBl. No 9/2000,
       
       and applicable also to tax liabilities which arose before promulgation of that amendment , in Paragraph 185(3) of the WAO, under which there is no claim to repayment where the economic burden of the duty was borne
      by a person other than the taxable person?̕  
      
         			(7)
         		
      23.  Article 10 EC, to which the Verwaltungsgerichtshof refers, requires Member States in particular to take all appropriate measures
      to ensure fulfilment of the obligations arising out of the EC Treaty, to facilitate the achievement of the Community̕s tasks,
      and to abstain from any measure which could jeopardise the attainment of the objectives of the Treaty.
      
      24.  Written and oral observations have been submitted by two of the claimants in the main proceedings – Karl Schlosser and Beta
      Leasing Gesellschaft mbH, both of whom operate restaurants in Vienna – by the Abgabenberufungskommission der Stadt Wien (Vienna
      Tax Appeals Board), whose decisions are contested, by the Austrian Government and by the Commission.  The Italian Government
      has submitted written observations and a third claimant – Ernestine Rathgeber, who runs a  
       Gasthaus  – submitted oral argument at the hearing.
       Assessment
      
      25.  As a preliminary point, I consider it appropriate to examine all the aspects of the disputed amendment referred to in the
      national court̕s question, and not only the issue of retroactivity which is stressed both in the question itself and in the
      Verwaltungsgerichtshof̕s reasoning.  The question whether the substantive rule is compatible with Community law logically
      precedes – and may affect the answer to – the question whether its retroactive effect is compatible.
      
      26.  Bearing that in mind, there is, as has been pointed out by the referring court and all those who have submitted observations,
      much in the Court̕s consistent case-law which is relevant to the various aspects of the present case.
      
      27.  On the one hand, it is established that individuals are entitled to reimbursement of national charges levied in breach of
      Community law, as a consequence and complement of the rights conferred on them by Community provisions as interpreted by the
      Court of Justice; Member States are therefore required in principle, as a matter of Community law, to repay such charges.
       
      
         			(8)
         		
      28.  However, in the absence of Community rules on such reimbursement, it is for the domestic legal system of each Member State
      to lay down the detailed procedural rules applicable, provided that they are not less favourable than those governing similar
      domestic situations (the principle of equivalence) and do not render the exercise of the rights conferred by Community law
      in practice impossible or excessively difficult (the principle of effectiveness).  
      
         			(9)
         		 The principle of equivalence
      
      29.  National rules on actions for the recovery of charges which are found to be incompatible with Community law may not be less
      favourable than those governing similar domestic actions, nor may such a charge be specifically targeted by more restrictive
      rules adopted following such a finding of incompatibility.  
      
         			(10)
         		
      30.  First of all in that regard, nothing in the wording of the amendment explicitly distinguishes between claims based on national
      law and those based on Community law.  Both the Abgabenberufungskommission and the Austrian Government have asserted that
      claims for reimbursement of a range of other taxes which they cite could be affected by the disputed amendment if those taxes
      were found to be contrary to national law.
      
      31.  Nor do I consider the circumstances of the adoption of the amendment to be of decisive importance in themselves.  Whilst it
      is clear that the imminent likelihood of a judgment of the Court of Justice finding the beverage tax to be incompatible with
      Community law was an important factor in the genesis and timing of the amendment, that does not mean that it applies or was
      intended to apply solely to claims for reimbursement of that tax or in general of taxes levied contrary to Community law.
      
      32.  The national court must none the less satisfy itself that the rule in issue does not in fact apply solely to a particular
      kind of charge declared incompatible with Community law but to ‘a whole range of internal charges and taxes̕.  
      
         			(11)
         		
      33.  In that regard, it is important to verify that factual or procedural circumstances do not transform a prima facie neutral
      rule, applicable without distinction, into one which in fact affects one type of claim much more significantly than another.
       Each rule must be examined in its procedural context.  
      
         			(12)
         		
      34.  In the present case, Beta Leasing points out that the amendment in issue excludes from its scope claimants ‘who are entitled
      to benefit from  
       Anlaßfallwirkung  in respect of a tax provision which has been held by the Verfassungsgerichtshof to be unlawful̕, but that there is no equivalent
      exclusion as regards findings of illegality by other national courts following a ruling of the Court of Justice.  Thus, it
      contends, if the Verfassungsgerichtshof had held the beverage tax to be unlawful and had limited its judgment in the same
      way, the amendment could not have had any effect.
      
      35.  The Commission explains that, since the effects of a finding that a tax is contrary to national constitutional law extend
      only to a limited number of parties,  
      
         			(13)
         		 problems of massive repayment such as those referred to in the present case cannot arise.  There had thus previously been
      no serious need for any rule precluding unjust enrichment in the manner specified in the disputed amendment.
      
      36.  In that light, the Commission originally considered that the rules governing reimbursement of taxes found incompatible with
      national law were not more favourable than in the case of taxes incompatible with Community law.  At the hearing however it
      changed its view and argued that there was a difference in treatment favouring those who claimed reimbursement of a tax found
      to be unlawful by the Verfassungsgerichtshof;  in such cases alone, where the claimant could benefit from  
       Anlaßfallwirkung , the possibility of unjust enrichment was no longer examined.
      
      37.  This aspect has not been discussed before the Court in great detail, and it would not be appropriate to express a definitive
      view which should be based on a full appreciation of national circumstances.  However, the contested amendment appears to
      mean that the rule precluding reimbursement where the burden of the tax has been passed on applies to all categories of claimant
      but one:  those who have brought proceedings before the Verfassungsgerichtshof challenging a tax declared unconstitutional
      by that court.
      
      38.  If it is the case that entitlement to benefit from  
       Anlaßfallwirkung  is confined to those bringing challenges under national constitutional law, then the rules governing reimbursement of taxes
      found incompatible with national law might be more favourable, in that regard, than in the case of taxes found incompatible
      with Community law.
      
      39.  For the amendment to comply with the principle of equivalence, it would be necessary either for the benefit of the exception
      to be extended to all those who have challenged a tax found to be incompatible with Community law or for the exception to
      be abolished entirely.
       The principle of effectiveness
      
      40.  The principle of effectiveness – that is to say of the effective enforcement of Community law in national courts and the effective
      protection by those courts of rights conferred by Community law – has been asserted by the Court in many areas, and may be
      seen as an expression of the generally recognised right to an effective judicial remedy.
      
      41.  As the Court has consistently expressed the principle, it is for the courts or tribunals of the Member States, pursuant to
      the principle of cooperation laid down by Article 10 EC, to ensure the legal protection arising for individuals from the direct
      effect of Community law.  
      
         			(14)
         		  Although the detailed procedural rules to be applied are a matter for national law, they must not render the exercise of
      rights conferred by Community law – here, the right to reimbursement of charges levied contrary to Community law – in practice
      impossible or excessively difficult.
      
      42.  When considering whether that is so, it is necessary to examine each rule in its context – its role in the national procedure
      viewed as a whole, having regard to all its features.  
      
         			(15)
         		
      43.  The types of rule which the Court has indicated as capable of making it in practice impossible or excessively difficult to
      recover charges levied contrary to Community law include in particular, in the context of unjust enrichment, certain presumptions
      or rules of evidence which place a burden of proof on the taxpayer  
      
         			(16)
         		 and certain procedural time-limits, particularly where they are applied retroactively.  
      
         			(17)
         		  I shall deal with those aspects below.
      
      44.  First, however, it is necessary to consider the concept of unjust enrichment itself.
       Unjust enrichment
      
      45.  Although Member States must in principle reimburse national charges levied in breach of Community law, they are not required
      to do so where that would entail the unjust enrichment of the recipient.  
      
         			(18)
         		  Legal systems in general do not recognise entitlement to any enrichment which would be unfair or unjustified, and no such
      entitlement is conferred by Community law.
      
      46.  In particular, in a case such as the present a Member State need not reimburse a trader where it is established that the burden
      of the charge paid by him has been passed on in its entirety to some other person and that the trader would be unjustly enriched
      by reimbursement;  if in the same circumstances the burden has been passed on in part, only the amount not passed on must
      be reimbursed.  
      
         			(19)
         		  A trader who has paid a tax but has in fact passed on the whole burden of it to his customers, without himself suffering
      any concomitant loss, will clearly be unjustly enriched if he then obtains reimbursement of that tax because it is found to
      have been unlawful.  
      
         			(20)
         		  A national rule precluding unjust enrichment in those circumstances is thus compatible with Community law. 
      
      47.  However, even where the burden of the charge has been passed on in whole or in part, repayment to the trader of the relevant
      amount does not necessarily entail his unjust enrichment.  
      
         			(21)
         		
      48.  For example, the trader may choose to curtail any increase in his retail prices and maintain his volume of sales by limiting
      his profit margin to absorb all or part of the tax.  Or else, having decided not to take that course but to increase his prices
      by the exact amount of the tax, he may find that his profits drop because he is making fewer sales.  And he may even choose
      to absorb part of the tax himself yet still find a drop in sales.  In all such cases – which are plausible in a situation
      of keen competition between traders – he will have suffered an economic loss as a result of the imposition of an unlawful
      tax, so that it cannot be said either that he has passed on (all) the burden of that tax to third parties or that he would
      be unjustly enriched if (an appropriate proportion of) the tax were reimbursed to him.  
      
         			(22)
         		
      49.  Community law thus does not allow a Member State to resist claims for reimbursement simply where the burden of a tax has been
      passed on;  it must also be established that unjust enrichment would ensue.  
      
         			(23)
         		
      50.  It is therefore necessary to look at any disputed rule carefully in order to be sure that it is truly limited to preventing
      unjust enrichment and does not also make it in practice impossible or excessively difficult to obtain reimbursement in other
      circumstances in which a right to reimbursement is required under Community law.
      
      51.  The disputed amendment to the Vienna tax code precludes repayment ‘where the economic burden of the duty has been borne by
      someone other than the taxable person̕.  The substance of that rule thus would not appear to affect any traders other than
      those who would indeed be unjustly enriched by reimbursement, provided that the concept of ‘bearing the economic burden̕ of
      a tax includes all suffering of economic loss as a result of being liable to pay it, whether the amount of the tax itself
      is billed to a third party or not, and provided that the rule is interpreted so that any sharing of the economic burden is
      taken into account and pro rata reimbursement may be obtained where appropriate.  Subject to those provisos, the substantive
      rule thus appears to respect the principle of effectiveness.
      
      52.  In that connection, the Commission drew attention at the hearing to an aspect which has not been debated in full detail before
      the Court.  If, as may have been the case, the amount of the beverage tax also had the effect of increasing the amount of
      VAT due on sales and thus the final retail price, traders̕ sales and thus profits may have been further affected.  That is
      one of the factors which, if applicable, must be taken into account before it can be decided that unjust enrichment would
      ensue from reimbursement.
       Burden of proof
      
      53.  More serious difficulty may arise with regard to requirements of proof, an aspect which is not governed by the disputed amendment
      itself.
      
      54.  It is clear from the case-law  
      
         			(24)
         		 that a rule requiring the claimant to prove that he has not passed on the tax to a third party, or a presumption that the
      tax has been passed on, does not comply with Community law.  Any rule imposing special limitations on the form of evidence
      which may be adduced also fails to comply.
      
      55.  According to the order for reference, the relevant tax code does not contain any special rules on the burden of proof, the
      evidence admissible or the assessment of that evidence.  The general procedural law applicable proceeds from the court̕s duty
      to ascertain the material circumstances  
       ex officio .  The taxable person must contribute to establishing the facts, but where proof cannot reasonably be expected the law is
      satisfied with establishment of probability, and admits as evidence anything which is capable of establishing the material
      facts and is appropriate in the circumstances of the case.  The Abgabenberufungskommission and the Austrian Government assert
      that the burden of proof is on the tax authorities.
      
      56.  The claimant Karl Schlosser contends however that under Austrian law, since a claim for reimbursement involves a request for
      treatment benefiting the claimant and verification that the statutory conditions for according that beneficial treatment are
      met, the claimant is under a duty to assist in establishing the relevant facts.  In particular he must provide documentation
      to support the calculations involved.  In the present cases, the Abgabenberufungskommission reached its decision by concluding,
      from the uncontested fact that the price charged to customers for alcoholic beverages was inclusive of beverage tax, that
      the economic burden of the tax had been borne by consumers.  That amounts to a presumption whereby reimbursement is rendered
      impossible or at least excessively difficult.
      
      57.  It is not for this Court to say which of those differing views of the implementation in practice of rules of national law
      is correct.  However, in order for the national court to be certain that the disputed amendment complies with Community law
      as regards requirements of proof, it must satisfy itself that the rules governing the ascertainment of the relevant facts
      are not biased against the claimant.
      
      58.  On the one hand there must be no obligation on the claimant to prove that he has not passed the burden of the tax on to a
      third party and no presumption that he has done so simply because his retail price was necessarily deemed to be inclusive
      of tax, regardless of any other circumstances.
      
      59.  On the other hand it is clear that, where a self-assessed tax is concerned, the tax authorities cannot be expected to prove
      that the burden has been passed on without the taxable person̕s cooperation and access to such relevant records as he may
      have kept.  
      
         			(25)
         		
      60.  In that context, it is in my view desirable to clarify the case-law by pointing out that, whilst Community law precludes any
      presumption of unjust enrichment to be refuted by the claimant, it does not preclude the possibility of drawing reasonable
      inferences from existing evidence.  Without such a possibility, the balance might be tilted so far in favour of the claimant
      as to render the justified aim of preventing unjust enrichment in practice impossible to achieve.  It must be possible for
      the deciding body to take all available relevant evidence into consideration and reach a fair decision taking full account
      of whatever likelihood there may be that the claimant bore any part of the burden of the tax or suffered any economic loss
      as a result of its imposition.
      
      61.  To conclude on this aspect, the national court must examine whether, in the context of the national procedural system viewed
      as a whole,  
      
         			(26)
         		 the disputed amendment has the effect in practice of establishing a presumption that the economic burden of the beverage
      tax was passed on to customers unless the trader can prove otherwise.  Such a situation would be contrary to Community law,
      and could be cured only by disapplying the disputed rule or by interpreting it in such a way that it did not have that effect.
       Retroactive effect
      
      62.  With regard to Community measures, the Court has repeatedly held that the principle of legal certainty precludes a measure
      from taking effect from a point in time before its publication, but that it may exceptionally be otherwise where the purpose
      to be achieved so demands and where the legitimate expectations of those concerned are duly respected.  
      
         			(27)
         		
      63.  In the context of national rules concerning the recovery of charges unduly levied, the Court has held that, where it has declared
      a charge to be contrary to Community law, the Member State in question is not precluded from adopting new conditions applying
      to its reimbursement, such as a shorter time-limit, provided that the principles of equivalence and effectiveness are observed.
       
      
         			(28)
         		
      64.  With regard to the latter principle, it must not adopt a procedural rule which specifically reduces the possibilities of bringing
      proceedings for recovery, in particular by retroactively reducing time-limits for bringing proceedings without making appropriate
      transitional arrangements.  
      
         			(29)
         		
      65.  The limitation of the temporal effect of the ruling in the  
       EKW  judgment does not mean that whenever a person had raised a claim before the date of the judgment that claim must be free
      from any other restriction laid down by national law but rather that, in relation to the period specified, no other claims
      may be allowed to proceed.  Nor is there is anything in the judgment which itself imposes or implies any general condition
      as to the date of enactment of any applicable national rules or which precludes any retroactive effect thereof. 
      
      66.  A national rule which does no more than preclude unjust enrichment is compatible with Community law.
      
      67.  Where such a rule applies to claims in respect of situations which arose before its enactment, that effect does not seem to
      me incompatible with Community law.  On the one hand, in so far as it seeks to preclude unjust enrichment, it in fact precludes
      only enrichment which would have occurred after its enactment, provided that there is no provision for recovery of any amount
      already reimbursed.  On the other hand, there can in any event be no legitimate expectation of any such enrichment, since
      the very concept of legitimacy cannot embrace what is unjust.
      
      68.  It is true that in other circumstances a retroactive effect may fall foul of the principle of effectiveness:  in  
       Marks & Spencer 
         			(30)
         		 and  
       Grundig Italiana ,  
      
         			(31)
         		 for example (to cite only the most recent cases), the Court has indicated that a retroactive reduction of the period within
      which reimbursement may be claimed is incompatible with the principle of effectiveness if, in the absence of adequate transitional
      provisions, it deprives some individuals of their right to reimbursement or allows them too short a period in which to assert
      that right.
      
      69.  Here, by contrast, since Community law does not require a right to reimbursement at all where unjust enrichment would ensue,
      the fact that, following a change to national law, a claim which might previously have succeeded can on that ground no longer
      succeed has no impact on the effectiveness of a right conferred by Community law.
      
      70.  However, the question of retroactivity is relevant to the question of the burden of proof since, as Mr Schlosser points out,
      claimants who know that they will have to establish certain facts are more likely to ensure that they have specific evidence
      of those facts than are those who do not.  
      
         			(32)
         		
      71.  To compile and retain such evidence may be a cumbersome task in situations such as the present, so that a trader might feel
      justified in not carrying it out if there were no current or foreseeable need to do so in order to be able to obtain reimbursement
      of a tax which he considered to be clearly incompatible with Community law and the imposition of which he knew caused him
      a loss.  In particular, retail price calculations may not have taken the amount of tax specifically and separately into account
      if the trader did not expect to have to provide proof of his loss.
      
      72.  A retroactive change in the rules would thus be incompatible with the principle of effectiveness if, by introducing an evidentiary
      requirement which was not anticipated at the time when the evidence could have been obtained, it made it in practice impossible
      or excessively difficult for such a trader to obtain reimbursement even when he had in fact borne (part of) the burden of
      the tax.
        Conclusion
      
      73.  In view of all the above considerations, I am of the opinion that the Court should give the following answer to the Verwaltungsgerichtshof:A provision of national law which precludes any reimbursement of a tax found incompatible with Community law to a taxable
      person where the economic burden of the tax has been borne by a third party is not contrary to Community law, even if it applies
      to situations which arose before its enactment and to parties whose right to rely on the incompatibility of the tax was not
      excluded by a temporal limitation of the effects of the judgment of the Court of Justice from which the incompatibility is
      deduced, provided that it complies with the principles of equivalence (it must not be less favourable than the rules governing
      reimbursement in comparable purely domestic situations) and effectiveness (it must not render in practice impossible or excessively
      difficult the exercise of rights conferred by Community law).In order to comply with the principle of effectiveness, the provision must not, in particular:
      –  render reimbursement in practice impossible or excessively difficult in respect of any part of the economic burden which has
      been borne by the taxable person, either because he has not passed on the full amount of the tax or because he has otherwise
      suffered economic loss as a result of its imposition; 
      
      –  entail, in practice, any presumption to the effect that the economic burden has been borne by a third party or any requirement
      that the claimant establish the contrary; 
      
      –  introduce any obligation to produce evidence which it is in practice impossible or excessively difficult to obtain at the
      time when the provision enters into force. 
      
      
      
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