56. In view of my proposed answer to the question referred for a preliminary ruling in so far as the question concerns the principle of sincere cooperation, there is no need also to examine the question in the light of Article 34(1) of the Charter. The brief comments below are therefore made only for the sake of completeness. In addition, they assume that the Court considers the Charter to be applicable retroactively to the facts of the main proceedings. (35)

57. It is settled case-law that the fundamental rights guaranteed in the legal order of the European Union are applicable in all situations governed by EU law, but not outside such situations. (36) As the Court stated in the judgment in Åkerberg Fransson (EU:C:2013:105), situations cannot exist which are covered by EU law without those fundamental rights being applicable. The applicability of EU law therefore entails applicability of the fundamental rights guaranteed by the Charter. (37) Where, on the other hand, a legal situation does not come within the scope of EU law, the Court does not have jurisdiction to rule on it and any provisions of the Charter relied upon cannot, of themselves, form the basis for such jurisdiction. (38)

58. In the present case, it is common ground that, in defining the conditions for eligibility for Belgian unemployment benefit, the national legislation at issue in the main proceedings does not implement an act of EU secondary legislation. In addition, it is clear from the above reasoning that Ms Melchior’s legal situation is purely domestic (39) and is not covered directly by a provision of the Staff Regulations or of the Conditions of Employment. (40) Furthermore, the Court has already held that the situation of an official does not fall within the scope of EU law simply because of the existence of an employment relationship with the European Union. (41)

59. Thus, it is only if the Court should, as I suggest, consider that Article 10 EC, read in conjunction with the provisions of the Conditions of Employment, is applicable to the dispute in the main proceedings that Ms Melchior’s situation would be governed by EU law and the Charter would therefore be applicable. (42)

60. Under Article 34(1) of the Charter, ‘[t]he Union recognises and respects the entitlement to social security benefits and social services providing protection … in the case of loss of employment, in accordance with the rules laid down by Union law and national laws and practices’. As is clear from its wording and from the Explanations relating to the Charter (43) (‘the Explanations’), that provision sets out a ‘principle’ (44) based on Articles 153 TFEU and 156 TFEU, Article 12 of the European Social Charter and point 10 of the Community Charter of Fundamental Social Rights of Workers. (45) In accordance with Articles 51(2) and 52(5) of the Charter, the provisions of the Charter which contain principles are addressed first and foremost to public authorities, have merely programmatic character (46) (as opposed to the prescriptive character of the provisions setting out ‘rights’) and require ‘implementing acts’. (47) With regard to their enforceability, they do not create, at least in the absence of ‘legislative implementation’, rights to positive action by the Member States’ authorities (48) and may be invoked in law only as interpretative references or as parameters for the ruling on the legality of the acts for their implementation. (49)

61. Here, the legislation at issue in the main proceedings represents the manifestation at national level of the principles of solidarity and protection which are expressed at EU level by Article 34(1) of the Charter. The application of such legislation in a situation covered by EU law must have due regard to that provision of the Charter. However, by precluding, for the purposes of entitlement to national unemployment benefits, the aggregation of periods of employment for which contributions have been paid to the national social security scheme and periods which have given rise to payment of contributions to the scheme established by the Conditions of Employment, in a situation like the present one the legislation at issue in the main proceedings, as interpreted and applied by the Belgian authorities, effectively denies the worker’s entitlement to social security benefits in the case of loss of employment, in contravention of the principle laid down in Article 34(1) of the Charter.

62. For the above reasons, I consider that, should the Court consider the Charter to be applicable ratione temporis to the facts of the main proceedings and conclude that the legislation at issue in the main proceedings, as interpreted and applied by the Belgian authorities, fails to comply with the Member States’ obligations stemming from the principle of sincere cooperation set out in Article 10 EC, read in conjunction with the Staff Regulations, that legislation would also be contrary to Article 34(1) of the Charter.