1 By judgment of 5 May 1988, which was received at the Court on 20 May 1988, the French Cour de cassation referred to the Court of Justice for a preliminary ruling under Article 177 of the EEC Treaty two questions on the interpretation of Article 51 of Council Regulation No 1408/71 of 14 June 1971 on the application of social security schemes to employed persons, to self-employed persons and to members of their families moving within the Community ( amended and updated by Council Regulation No 2001/83 of 2 June 1983, Official Journal 1983, L 230, p . 6 ).
2 These questions were raised in the course of proceedings between Alan Jordan, a British national, and the Caisse nationale d' assurance vieillesse des travailleurs salariés ( hereinafter referred to as "CNAVTS "), a French social security institution .
3 Mr Jordan worked as an employed person in the United Kingdom and in France . With effect from 1 January 1979 an old-age pension was granted to him by each of those Member States in pursuance of Article 46 of Regulation No 1408/71 . That article provides that, when a worker has been subject to the legislation of more than one Member State, the competent institution of each Member State must make a comparison between the benefit to be paid on the basis of national legislation alone and the benefit payable as a result of aggregation and apportionment provided for in Article 46(2 ). Only the higher of the two amounts is to be paid .
4 Since 1979, Mr Jordan has disputed the amount thus calculated by CNAVTS . In particular he claims entitlement to a supplementary allowance by the fonds national de solidarité ( National Solidarity Fund ) In Mr Jordan' s view, that allowance, representing a minimum non-contributory benefit, is available only to French nationals, which is contrary to Article 50 of Regulation No 1408/71 .
5 The French social security system was amended by Order 82-270 of 26 March 1982 ( Official Journal of the French Republic of 28 March 1982, p . 951 ) and Law 83-430 of 31 May 1983 ( Official Journal of the French Republic of 1 June 1983, p . 1639 ). Those measures provided for an increase in benefits to raise the old-age benefit to a minimum amount for insured persons who had completed not less than 150 quarterly periods of insurance; that amount was to be apportioned in the case of insured persons who had completed a smaller number of quarterly insurance periods . For old-age pensions taking effect after 1 April 1983, the new benefit replaced both the contributory old-age benefit and the supplementary allowance paid by the national solidarity fund . However, as regards benefits awarded before 1 April 1983, the former system remained in force .
6 By a judgment of 15 February 1985, the cour d' appel ( Court of Appeal ), Poitiers decided that, although Article 50 of Regulation No 1408/71 did not confer entitlement to an allowance from the national solidarity fund, Article 51(2 ) of that regulation required that there should be a fresh calculation of the benefit and that, consequently, Mr Jordan could claim the minimum benefit in pursuance of the new French regulations . CNAVTS appealed on a point of law against that judgment .
7 Taking the view that the dispute raised a problem concerning the interpretation of Regulation No 1408/71, and in particular Article 51 thereof, the Cour de cassation stayed the proceedings and referred to the Court of Justice the following two questions for a preliminary ruling : "1 . Are the alterations made by the legislation of the competent State to the method of determining the minimum old-age benefit covered by paragraph ( 1 ) or paragraph ( 2 ) of Article 51 of that Regulation? 2 . Must the rule set out in Article 51(2 ) be applied without any restriction, notwithstanding any provision of national legislation determining the date when the alterations to the method of determining or the rules for calculating benefits are to come into force and excluding from their scope of application pensions awarded prior to that date?"
8 Reference is made to the Report for the Hearing for a fuller account of the facts of the case, the course of the procedure and the written observations submitted to the Court, which are mentioned or discussed hereinafter only in so far as is necessary for the reasoning of the Court .
9 As regards the first question, it should be noted at the outset that Article 46(2 ) of Regulation No 1408/71 confers on a migrant worker the right to receive the most favourable benefit resulting either from the application of national legislation alone or from aggregation and apportionment . This right entails in principle that whenever one of the benefits in question is altered, a fresh comparison should be made, in accordance with Article 46(1 ), between the two systems in order to determine which is the most advantageous benefit following that alteration .
10 However, in order to reduce the administrative burden which a fresh examination of the insured' s situation following every alteration to the benefits received would represent, Article 51(1 ) excludes recalculation of benefits where the alterations are the consequences of the general evolution of the economic and social situation ( see judgment of 2 February 1982, in Case 7/81 Sinatra v FNROM (( 1982 )) ECR 137 ). On the other hand, that exclusion does not apply to alterations in benefits due to a change in the personal circumstances of the insured or in the criteria for granting a benefit . Article 51(2 ) provides that the latter alterations give rise to a recalculation pursuant to Article 46 .
11 Therefore, the answer to be given to the first question is that Article 51 of Regulation No 1408/71 must be interpreted as meaning that an alteration in the method of determining the minimum old-age benefit falls within the scope of paragraph ( 2 ) of that article .
12 The second question seeks to ascertain whether an alteration in the method of determining or the rules for calculating old-age benefits which is not applicable to pensions awarded before its entry into force, requires the Member State concerned to carry out a recalculation in pursuance of Article 51(2 ) of Regulation No 1408/71 .
13 The Court has consistently held that Article 51 of the Treaty merely provides for the coordination of the legislation of the Member States and leaves in being differences between the Member States' social security systems and in the rights of workers employed in the Member States ( see in particular the judgment of 18 January 1986 in Case 41/84 Pinna v Caisse d' allocations familiales de la Savoie (( 1986 )) ECR 1 ).
14 It follows that the decision when an alteration in the criteria for granting a benefit takes effect is for the Member States . Where the amendment to the national rules affects only pensions paid after the date when it came into force, Article 51 of Regulation No 1408/71 does not apply and it is therefore not necessary to carry out a recalculation in accordance with Article 46 of that regulation .
15 As the French Government observes, that interpretation of Article 51 does not give rise to discrimination prohibited by Articles 7 and 48 of the Treaty and by Regulation No 1408/71 in the case of workers who have exercised their right to freedom of movement . Those workers will continue to be governed by the former regulations, in the same way as other workers subject to the scheme of the same Member State whose pensions were awarded before the entry into force of the amended regulations .
16 The answer to the second question should therefore be that Article 51(2 ) of Regulation No 1408/71 must be interpreted as meaning that an alteration in the method of determining or the rules for calculating old-age benefits which is not applicable to pensions awarded before that alteration came into force, does not require the Member State concerned to carry out a recalculation .