OPINION OF ADVOCATE GENERAL

Kokott

delivered on 29 March 2007 ( )

Joined Cases C‑231/06 to C‑233/06

Émilienne Jonkman and Others

(References for a preliminary ruling from the Cour du travail, Brussels (Belgium))

(Social policy – Social security for employed persons – Equal treatment of men and women– Statutory pension scheme – Special scheme for air crew – Procedure for adjustment – Arrangements for retroactive insurance of a category of persons originally excluded – Gender discrimination – Principle of effectiveness)

I – Introduction

1. The object of the present references for a preliminary ruling is yet again the legal status of Belgian air hostesses in comparison with their male colleagues, a subject which was brought before the Court as early as the 1970s and led to its three Defrenne ( ) judgments. The case-law having since then considered in particular the principle of equal pay for men and women and their equal treatment in terms of conditions of employment in a number of cases, this case returns to the starting theme of the Defrenne case-law, namely the issue of equal treatment of men and women as regards statutory pension schemes.

2. From 1964 to 1980, the statutory pension scheme in Belgium included a special scheme for male cabin crew, allowing them to obtain a higher pension than was otherwise available under the scheme which applied generally to employees. However, for that purpose they had to pay higher pension contributions.

3. This special scheme has been available to female cabin crew only since 1981. ( ) For periods during which they made contributions before 1981, female cabin crew could obtain the benefit of the special scheme retroactively only if they made retroactive contributions. For this purpose an ‘adjustment procedure’ was created in 1997, which required the persons concerned to pay adjustment contributions in the form of a single global payment, plus 10% interest per annum from the end of the relevant contribution year.

4. The present proceedings seek to have this adjustment procedure, which enables equal treatment for the persons concerned only at significant financial cost, considered by reference to Community law. The question is whether the arrangements for retroactive contributions as now provided for in Belgian law for former air hostesses do not deprive the principle of equal treatment of men and women of practical effect.

II – Legal framework

A – Community law

5. Council Directive 79/7/EEC ( ) aims at the progressive implementation of the principle of equal treatment for men and women in matters of social security. Article 3(1)(a) provides that the directive applies inter alia to statutory schemes which provide protection against the risk of old age.

6. Article 4(1) of Directive 79/7 provides as follows:

‘The principle of equal treatment means that there shall be no discrimination whatsoever on ground of sex either directly, or indirectly by reference in particular to marital or family status, in particular as concerns:

– the scope of the schemes and the conditions of access thereto,

– the obligation to contribute and the calculation of contributions,

– the calculation of benefits including increases due in respect of a spouse and for dependants and the conditions governing the duration and retention of entitlement to benefits.’

7. The transposition period for Directive 79/7 expired on 23 December 1984. ( )

B – National law

8. With effect from 1 January 1964, a special scheme for ‘civil aviation air crew’ was introduced into the statutory pension scheme, which derogated from the general retirement and survivors’ pension scheme for employees. After re-enactment of the relevant provisions in 1969, the Royal Decree of 3 November 1969 ( ) is the relevant legal basis for this special scheme.

9. The essential feature of the special scheme is that for air crew a larger part of their salary is taken into account both as regards levying of pension contributions and as regards calculating pension payments than in the general scheme for employees. Thus, those favoured by the special scheme could enjoy a higher pension than members of the general scheme for employees, although to do so they had also to pay higher pension contributions than the rules of the general scheme required.

10. Female air crew were originally expressly excluded from the special scheme, ( ) with the effect that they had correspondingly lower pension entitlements. ( ) It was not until a Royal Decree of 27 June 1980 ( ) that, with effect from 1 January 1981, the advantages of the special scheme were extended to air hostesses, albeit not retroactively. Accordingly, as regards contribution periods between 1 January 1964 and 31 December 1980 the amounts of contributions and of pensions for air hostesses continued to depend on the general scheme for employed persons.

11. A Royal Decree of 25 June 1997 ( ) was intended finally to ensure equal treatment of male and female air crew in respect of the period referred to of 1 January 1964 to 31 December 1980. For this purpose an ‘adjustment procedure’ was inserted into the Royal Decree of 3 November 1969, which allowed affected air hostesses to benefit from pensions calculated on the same basis as those of male air crew, by means of retroactive contributions. These retroactive contributions are to be made by means of adjustment contributions by the persons concerned in the form of a single global payment for their periods of service between 1 January 1964 and 31 December 1980, plus 10% interest per annum from the end of the relevant contribution year.

12. The details of this adjustment procedure are laid down by the new Article 16b of the Royal Decree of 3 November 1969, ( ) paragraphs 2 and 4(3) of which provide as follows:

‘…

§ 2. Entitlement under the provisions of paragraph 1 (adjustment) is subject to payment in full of the employer’s and the employee’s pension contributions due under the special scheme for civil aviation air crew, after deduction of the amount of the employer’s and employee’s pension contributions paid as an employed person.

…

§ 4. … Simple interest, calculated at the rate of 10% per annum, is due for the period beginning at the end of each calendar year of the period subject to adjustment and ending on the date of the application for adjustment.

…’

13. In addition, letter (b) of Paragraph 9(2) of Article 16b of the Royal Decree of 3 November 1969 provides that the recalculation of pension payments pursuant to the adjustment procedure shall take effect only when an application to make retroactive contributions is made, and only in respect of the future.

III – Facts and main proceedings

14. The subject of the main proceedings is disputes between three former air hostesses who used to work for the Belgian airline Sabena ( ) and the Belgian Office national des pensions (‘ONP’) ( ) concerning the calculation of their pensions. In essence, the three claimants in the main proceedings want their pensions to be calculated according to the special scheme for civil aviation air crew, which is to their advantage, without having to make retroactive contributions at a high financial cost for the period before 1 January 1981. However, the ONP rejects this claim.

15. In Case C‑231/06, by decision of 24 March 1997, the ONP granted to Ms Émilienne Jonkman, born on 24 February 1938, a retirement pension at the rate for single persons of an annual amount of BEF 536 960 (EUR 13 311) from 1 February 1997. The pension was calculated on a career record of 27/34, that is to say on the basis of the years 1966 to 1992 during which Ms Jonkman worked as an air hostess.

16. In Case C‑232/06, by decision of 6 May 1996, the ONP granted to Ms Hélène Vercheval, born on 25 June 1941, a retirement pension at the rate for single persons of an annual amount of BEF 682 915 (EUR 16 929) from 1 July 1996. That pension was calculated on a career record of 33/34 on the basis of an accepted professional career from 1963 to 1995 inclusive as an air hostess.

17. Finally, in Case C‑233/06, by decision of 16 December 1996, confirmed on 22 September 1997, the ONP granted to Ms Noëlle Permesaen, born on 3 January 1942, a retirement pension at the rate for single persons of an annual amount of BEF 676 734 (EUR 16 776) from 1 February 1997. That pension was calculated on the basis of a career record of 31/34 on the basis of an accepted professional career from 1966 to 1994 inclusive as an air hostess.

18. Ms Jonkman, Ms Vercheval and Ms Permesaen each brought an action against these decisions at the Tribunal du travail, ( ) Nivelles, and complained of continuing discrimination against air hostesses by comparison with male air crew in respect of pension calculations for years before 1981.

19. After two of the claimants, Ms Jonkman and Ms Vercheval, succeeded at first instance, the ONP appealed against the respective judgments of the Tribunal du travail, Nivelles. ( ) In the third set of proceedings, by contrast, the claimant, Ms Permesaen, succeeded only in part; she appealed against the judgment of the Tribunal du travail, Nivelles. ( ) Thus, all three main proceedings come to be before the Brussels Cour de travail ( ) (‘the national court’) on appeal.

IV – Request for a preliminary ruling and proceedings before the Court

20. By judgments dated 10 May 2006, the Brussels Cour du travail referred the following questions in Cases C‑231/06, C‑232/06 and C‑233/06 to the Court for a preliminary ruling:

(1) With regard to the adjustment contributions ( )

Is Directive 79/7/EEC … to be interpreted as meaning that it authorises a Member State to adopt rules intended to allow a category of persons of a particular sex, originally discriminated against, to become eligible for the pension scheme applicable to the category of persons of the opposite sex by making retroactive payment (a single payment of a very large sum) of contributions, recovery of which would be time-barred under the legislation applicable in that State in the case of the latter category of persons?

If so, is not Directive 79/7/EEC … to be interpreted as requiring a Member State to amend legislation contrary to that provision as soon as a judgment of the Court of Justice of the European Communities rules that there is a conflict of norms and, at the very least, within the applicable time-limit for recovery of the contributions which have become payable by virtue of the adoption of those rules?

(2) With regard to the interest for late payment ( )

Is Directive 79/7/EEC … to be interpreted as meaning that it authorises a Member State to adopt rules intended to allow a category of persons of a particular sex, originally discriminated against, to become eligible for the pension scheme applicable to the category of persons of the opposite sex by making payment of a large amount of late payment interest, recovery of which would be time-barred under the legislation applicable in that State in the case of the latter category of persons?

If so, is not Directive 79/7/EEC … to be interpreted as requiring a Member State to amend legislation contrary to that provision as soon as a judgment of the Court of Justice of the European Communities rules that there is a conflict of norms and, at the very least, within the applicable time-limit for recovery of late payment interest due as a result of the adoption of those rules?

21. By order dated 21 June 2006, the President of the Court of Justice joined Cases C‑231/06, C‑232/06 and C‑233/06 for the purposes of the written and oral procedure and for judgment.

22. In the proceedings before the Court, in addition to the parties to the three sets of main proceedings the Commission of the European Communities has made written and oral submissions, and the Italian Government took part in the written procedure.

V – Analysis

A – Preliminary remarks

23. In the present case there is no dispute that in Belgium between 1964 and 1980 air hostesses suffered direct discrimination on the ground of sex, because within the framework of the statutory pension scheme the advantages of the special scheme for civil aviation air crew were denied them.

24. All that is in dispute is whether the adjustment procedure introduced in 1997 which was intended to remove all discrimination is itself compatible with the principle of equal treatment of men and women in the field of social security, as expressed in Directive 79/7.

25. The adjustment procedure referred to is based on the principle of retroactive contributions. Women who wish to take advantage of the benefits conferred by the special scheme are required to pay, first, adjustment contributions in the form of a single global payment and, second, interest on such adjustment contributions of 10% from the end of the relevant calendar year in the adjustment period. Both can impose significant financial burdens on the persons concerned.

26. The national court has made these features of the adjustment procedure the subject of both the questions it has referred. In essence it asks whether the principle of equal treatment of men and women precludes a provision for retroactive contributions which involves significant financial burdens on the persons concerned.

27. In this connection the national court rightly refers to Directive 79/7. Admittedly, the time-limit for transposing this directive is long after the contribution periods in question in the present case of 1964 to 1980. ( ) However, the fact that the directive does not contain any provisions to the contrary means that it is applicable to all future (as well as, of course, to all present) effects of factual situations arising under the previous law. ( ) It follows that the principle of equal treatment of men and women under Directive 79/7 must be applied to grants of pensions when claimed today by the claimants in the three main proceedings under the special scheme for civil aviation air crew.

B – The two questions referred

28. Given that the answer to the references for a preliminary ruling depends on the same considerations both as regards the adjustment contributions and as regards interest on them, I propose to consider both questions together.

1. The adjustment payments and interest on them in light of the principle of equal treatment

29. Article 4(1) of Directive 79/7, on which individuals can rely directly, ( ) provides that the principle of equal treatment of men and women in the area of social security includes a requirement that there shall be no discrimination whatsoever on ground of sex either directly or indirectly as regards the conditions of access to statutory pension schemes and the calculation of benefits thereunder.

30. This provision gives expression to the principles of equal treatment and of non-discrimination, which are general principles of Community law and which have been consistently held to require that similar situations are not treated differently and different situations are not treated in the same way, so far as such treatment is not objectively justified. ( )

31. If a pensions contribution scheme is designed originally such that it benefited only one sex, the principle of equal treatment requires that workers discriminated against be placed in the same situation as workers of the other sex. ( ) In practice this means two things:

32. First, such a scheme must – until it is either discontinued or amended – be extended to persons of the other sex, in order to remove the discrimination against them. ( )

33. Second, persons of the sex discriminated against cannot demand to be treated better in financial terms than if the scheme in question had been open to them from its inception; therefore, in particular, they cannot avoid making retroactive pension contributions for the period in question if they wish to claim the benefits of the special scheme. ( )

34. Against this background, there can in principle be no complaint that an adjustment procedure such as the Belgian one confers the benefits of the pension scheme for civil aviation air crew on the air hostesses originally excluded only if they make retroactive contributions by means of retroactive payments.

35. If one now conferred the benefits of the special scheme on former air hostesses without requiring them to make contributions corresponding to those their male colleagues made, then this would ultimately lead to unjustified equal treatment of substantially different situations: both categories of person would receive pensions calculated by reference to the more favourable special scheme, but only male air crew would have paid for this benefit by means of correspondingly higher pension contributions. At that time their female colleagues paid only the smaller contributions required by the general pension scheme and therefore received a higher net income.

36. Thus, an unjustified advantage would arise in favour of former air hostesses if one now granted them a higher pension, calculated in accordance with the special scheme, without requiring them to make adjustment payments pursuant to retroactive contribution provisions. ( )

37. However, whether it is also legitimate to require the payment of interest on such adjustment payments, having regard to the principle of equal treatment, depends on the specific structure and purpose of the particular interest provision.

38. There could be no complaint if, in the context of retroactive contributions, interest were charged on the adjustment payments for the purpose of adjusting for purchasing power in order to take account of inflation since the relevant time. Indeed, it would even be an expression of the equal treatment of all members within the meaning of Article 4(1) of Directive 79/7 if adjustment payments by air hostesses corresponded to the pension scheme contributions their male colleagues made during a comparable career record not only nominally but also in real terms.

39. The imposition of interest for the purpose of adjusting for purchasing power is, however, permissible only to the extent that inflation is not already taken into account in calculating the amounts of the adjustment payments. If the adjustment payments themselves are calculated taking inflation into account, inflation cannot be taken into account a second time by means of interest. At the oral hearing before the Court the ONP’s representative was not able to say definitively whether the adjustment payments demanded from the former air hostesses pursuant to the 1997 adjustment regulations already contained an element of purchasing power adjustment.

40. The Member States must be given discretion in determining what interest may be required in order to adjust for purchasing power. A flat rate of interest which on average ensures an appropriate adjustment for inflation must also be regarded as permissible to that extent. Only an interest rate that went beyond what was necessary to adjust for purchasing power would be incompatible with the principle of equal treatment, if it meant that persons originally discriminated against were required to pay contributions that were higher than those payable by other members not only nominally but also in real terms.

41. Irrelevant, however, is the interest rate former air hostesses could have obtained if they had invested the amount by which their net salaries exceeded those of their male colleagues on the capital markets each month from 1964 to 1980, that is the amount by which the contributions their male colleagues made to the special scheme exceeded the pension contributions generally required at that time in Belgium. This is because air hostesses were under no obligation to build up an additional, private pension fund of their own, or to set aside savings in case subsequent retroactive contributions were required. It follows that one cannot criticise them today for not having built up corresponding private savings.

42. It would be likewise inappropriate to require former air hostesses to pay interest on account of delay. As the claimants in the main proceedings rightly submitted, in the material period of 1964 to 1980 the law then in force in Belgium did not even permit them to make pension contributions under the special scheme for civil aviation air crew. The fact that they are able to make these contributions only now, retroactively, is not caused by any failure on the part of the air hostesses but is the direct consequence of the national legal system at the time which discriminated against them.

43. The references for a preliminary ruling simply assume that in the present case the persons concerned are required to pay interest on account of delay. ( ) It is for the national court to reconsider in detail whether interest of 10% per annum, as provided for by the 1997 adjustment provisions, is not at least in part intended to adjust for purchasing power in relation to inflation since contribution years 1964 to 1980. However, if the latter is the case the interest charge is legitimate only to the extent that it does not exceed what is necessary to make a reasonable adjustment for purchasing power.

44. Thus, by way of interim conclusion it is to be held that:

A national provision intended to allow a category of persons of a particular sex, originally discriminated against, to become eligible for the more favourable pension scheme applicable to the category of persons of the opposite sex is not rendered incompatible with Directive 79/7 solely by the fact that it requires the persons concerned in making retroactive contributions

– to make adjustment payments

and

– to pay interest on such adjustment payments, to the extent that the interest is not interest for late payment and does not exceed what is necessary to make a reasonable adjustment for purchasing power.

2. The requirement for effective enforcement of the right to equal treatment

45. Even if, in principle, a requirement for retroactive contributions is unobjectionable in terms of equal treatment of men and women, there remains to be considered whether a provision such as the Belgian one, which involves serious financial burdens on the persons concerned, can have effect having regard to the principle of equal treatment as laid down by Directive 79/7.

46. The principle of effectiveness ( ) requires that the relevant provisions of national law may not render the enforcement of the right of persons concerned to equal treatment practically impossible or excessively difficult. The discretion which Member States have in the field of social policy cannot result in the undermining of a fundamental principle of Community law, such as that of equal treatment. ( )

47. The three claimants in the main proceedings have submitted without contradiction that the adjustment contributions they would be required to pay retroactively in the form of a single global payment, including interest, would amount to more than EUR 60 000, ( ) interest alone, at more than EUR 40 000, constituting the lion’s share of this amount.

48. It is obvious that the requirement to make a single global payment of the order of this amount renders it practically impossible, or at least excessively difficult, for the persons concerned to make retroactive contributions and thus to claim the benefits of the special scheme for civil aviation air crew.

49. In this context, it is in particular to be recalled that the persons concerned are already retired and, according to the ONP’s pension decisions, their pensions are between EUR 13 311 and EUR 16 929 per annum, which corresponds to a monthly pension of less than EUR 1 500. Accordingly, the single global payment, which must be made in advance, would be many times the annual pensions of the persons concerned, and even the retroactive payment of interest-free adjustment contributions would be significantly more than one year’s pension, being a single payment of approximately EUR 20 000.

50. It follows that in order to make retroactive contributions, the persons concerned would have to draw on their savings to a significant extent, and might even have to go into debt. It is obvious that from the point of view of the claimants, who are no longer earning, this would be economically irrational. In case of doubt, the persons concerned would tend not to make retroactive contributions, because the financial burdens involved in doing so would be disproportionate to the increase in pension that could be achieved, of around EUR 2 500 per annum (EUR 208 per month). ( )

51. Accordingly, the claimants rightly submit that an adjustment procedure such as the Belgian one is not compatible with the principle of effectiveness and in reality perpetuates the discrimination they suffered.

52. In order not to thwart the effective enforcement of the right to equal treatment, the persons concerned would have to be permitted to pay their adjustment contributions and any interest on them by monthly payments instead of by a single global payment. ( ) The postponed payment of the remainder of the relevant amount would contribute decisively to making the economic burden tolerable for the persons concerned.

53. Such an instalment model would not in any way lead to unlawful better treatment of the former air hostesses by comparison with their male colleagues, ( ) but would on the contrary contribute to making their respective contribution burdens comparable, as the principle of equal treatment requires. ( ) In any event, male air crew were not required to pay their pension contributions all at once, which were instead required to be paid over a period of years, or even decades, in the form of monthly payments, which were in addition tax deductible. ( )

54. The amount of the monthly payments must always be calculated taking all the circumstances of the individual case into account. In that regard, an appropriate starting point is the fact that the adjustment payments and any interest on them should be paid in full in the period during which it is anticipated that the pension will be paid.

55. However, in order to satisfy the principle of effectiveness, the total monthly burden on the persons concerned must be limited so that their retroactive contributions can give them a material benefit despite the adjustment payments and any interest that must be paid. Accordingly, the instalments of adjustment payments including interest must not take up the whole of the increase in monthly pension which a former air hostess may expect from claiming under the special scheme. It would for example be reasonable to retain approximately half of the resulting increase in pension as an instalment payment and to pay out the other half to the pensioners. ( )

56. It is correct to point out that the application of such a scheme of limited instalment payments allows the persons concerned to receive an increase in pension before they have paid all the contributions actuarially required. Indeed, it is possible that the persons concerned do not pay all the necessary adjustment payments during the period their pension is paid. ( ) There is no doubt that this can lead to a certain increase in the financial burden on the State pension scheme.

57. However, the Member State whose legislation is the real cause of this discrimination on the ground of sex, and the institution operating the statutory pension scheme, must also bear any financial burdens which accompany the effective enforcement of the principle of equal treatment. Purely budgetary considerations cannot justify discrimination on the ground of sex. ( ) Nor can they be pleaded later, when the issue is how to eliminate the consequences of past discrimination effectively.

58. In any event, in the present case neither the Belgian Government ( ) nor the ONP has submitted any evidence that granting former air hostesses the benefits of the special scheme for civil aviation air crew before full payment of all adjustment contributions plus any interest would create a serious risk to the financial stability of the State pension scheme. ( )

59. Apart from anything else, it appears that in adopting the adjustment regulations the Belgian legislature did not take the approach that retroactive contributions by former air hostesses had to be neutral in budgetary terms. The 1997 adjustment regulations provide that only employee contributions are to be levied retroactively for contribution periods from 1964 to 1980, whereas employers are expressly exempted from retroactive payment of the pension contributions imposed on them. ( )

60. Accordingly, by way of interim conclusion it is to be held that:

A national provision intended to allow a category of persons of a particular sex, originally discriminated against, to become eligible for the more favourable pension scheme applicable to the category of persons of the opposite sex is incompatible with Directive 79/7 to the extent that it involves such high financial burdens for the persons concerned in the form of single global payments that it makes retroactive contributions practically impossible or excessively difficult for them. It may be that payment by instalments must be permitted, the amount of those instalments being calculated so that, despite the adjustment contributions and any interest, the retroactive contributions can confer a material benefit on the persons concerned.

C – Final remarks

1. Commencement of retroactive contributions

61. During the oral hearing before the Court, it was pointed out that the Belgian 1997 adjustment regulations provide that any retroactive contributions have effect only for the future, so that the persons concerned can expect an increase in pension only in respect of the period after their application to make retroactive contributions. ( )

62. In principle, the enactment of reasonable exclusion provisions is compatible with Community law provided that the principles of equivalence and of effectiveness are observed. Accordingly, the Court has held that the Member States may lay down time-limits for raising proceedings, provided those principles are observed. ( )

63. In the same way, it must be possible to confer an increase in pension required by Community law on persons originally discriminated against only with effect from the date of the application and only for the future. Of course, this presupposes that any correction of other errors in calculating pension entitlements takes effect under national law only for the future (principle of equivalence). ( )

64. However, in that regard it is to be observed that a pension increase which is conferred only for the future cannot require the same amount of adjustment payments as a pension increase paid to the persons concerned retroactively. The principle of equal treatment requires the adjustment payments to be reduced and in this way account to be taken actuarially of the fact that the persons concerned will receive a higher pension not from the time they attain retirement age, but only from the significantly later time when they apply to make retroactive contributions.

65. Accordingly, if the national court holds that retroactive insurance for the claimants in the three sets of main proceedings has effect only for the future but still requires a special application, their adjustment payments and any interest on them are to be reduced accordingly. By contrast, if the national court concludes that the claimants’ appeals in the three sets of main proceedings against their pension notices constitute by implication applications to make retroactive contributions, the higher pension is to be awarded to them retroactively. In the latter case, the ONP can set off the adjustment payments due and any interest thereon against the pension increases payable retrospectively for the period from the attainment of pensionable age.

2. Limitation as regards contributions and interest

66. In its request for a preliminary ruling, the national court points out in particular that the limitation period for actions against male air crew for payment of contributions and interest in respect of the disputed period of 1964 to 1980 has already expired.

67. However, this in itself is not sufficient to prevent female air crew from being required to pay adjustment payments and interest if they wish to claim benefits under the special scheme for civil aviation air crew by means of retroactive contributions.

68. In terms of limitation periods, contributions by male air crew in respect of the period from 1964 to 1980 are not comparable to adjustment payments that female air crew have to make if they apply to make retroactive contributions. The respective liabilities to pay contributions do not arise at the same time and accordingly the time-limits for raising an action need not expire at the same time. On the contrary, it is only natural that liabilities to pay contributions and interest which have arisen earlier are subject to limitation earlier than those which arise only at a later stage, in consequence of an application by the person concerned to make retroactive contributions.

69. If one were to regard any action for payment of the adjustment payments and interest due by the former air hostesses as being precluded by limitation from the very beginning, the principle of retroactive contributions would be devoid of substance, and female air crew would in fact be in a better position than male air crew. Such a result would be incompatible with the principle of equal treatment of men and women. As already mentioned, ( ) the members of the category of persons so far discriminated against cannot relieve themselves of liability to make retroactive pension contributions in respect of the period in question by reference to the principle of equal treatment.

70. However, the same limitation periods must of course apply for adjustment payments (including, as the case may be, those to be paid by instalments) and interest payable by female air crew from the time the respective liability arises as apply to pension contributions and interest payable by male air crew in respect of contribution years 1964 to 1980.

3. Restriction of the temporal effects of the judgment

71. In some of the cases which have concerned equal treatment of men and women, the Court has restricted the temporal effects of its judgment by reference to the principle of legal certainty. ( )

72. However, according to consistent case-law such a restriction is possible only by way of exception, ( ) and only where two conditions are fulfilled. ( ) First, there must be a risk of serious economic repercussions owing in particular to the large number of legal relationships entered into in good faith on the basis of rules considered to be validly in force. Second, it must appear that both individuals and national authorities have been led into adopting practices which do not comply with Community legislation by reason of objective, significant uncertainty regarding the implications of Community provisions, to which the conduct of other Member States or the Commission may even have contributed.

73. In the present case, the first condition is in any event not fulfilled. As already stated, neither the Belgian Government nor the ONP has provided evidence that the solution put forward above gives rise to any fear of serious economic repercussions, such as the risk of a significant danger to the financial stability of the State pension scheme.

74. Accordingly, there is no reason for the Court to restrict the temporal effects of its judgment in the present case.

VI – Conclusion

75. In the light of the foregoing observations, I suggest to the Court that it should answer the Brussels Cour de travail as follows:

(1) A national provision intended to allow a category of persons of a particular sex, originally discriminated against, to become eligible for the more favourable pension scheme applicable to the category of persons of the opposite sex is not rendered incompatible with Directive 79/7 solely by the fact that it requires the persons concerned in making retroactive contributions

– to make adjustment payments

and

– to pay interest on such adjustment payments, to the extent that the interest is not interest for late payment and does not exceed what is necessary to make a reasonable adjustment for purchasing power.

(2) However, such a provision is incompatible with Directive 79/7 to the extent that it involves such high financial burdens for the persons concerned in the form of single global payments that it makes retroactive contributions practically impossible or excessively difficult for them. It may be that payment by instalments must be permitted, the amount of those instalments being calculated so that, despite the adjustment payments and any interest, the retroactive contributions can confer a material benefit on the persons concerned.