Moreover, it follows from the wording of that provision that overlapping occurs not only when one person is entitled to two different family benefits at the same time, but also when two different persons — in this case two parents — are entitled to such benefits in respect of the same child. The spirit of the provisions of Regulation No 1408/71 governing the overlapping of family benefits and the solutions therein provided for in the event of overlapping demonstrate that the aim of the provision in question is to prevent not only the direct recipient of a family benefit, namely the worker, but also the indirect recipients thereof, that is to say the members of the worker’s family, from receiving two benefits of the same kind at the same time.

In view of the numerous differences between the national social security schemes, if the basis for the calculation and the conditions for the grant of benefits were required to be exactly the same, the prohibition on overlapping benefits contained in Article 12 of Regulation No 1408/71 would be applied to a considerably lesser extent. Such a result would run counter to the aim of that prohibition, which is to obviate unjustified duplication of social security benefits.

Social security benefits must be regarded, irrespective of characteristics peculiar to the various national laws, as being of the same kind when their purpose and object together with the basis on which they are calculated and the conditions for granting them are identical. On the other hand, characteristics which are purely formal cannot be regarded as relevant criteria for the purpose of classifying benefits.

Articles 1(u)(i) and 4(1)(h) of Regulation No 1408/71, in the version amended and updated by Regulation No 118/97, as amended by Regulation No 1606/98, and Article 10(1)(b)(i) of Regulation No 574/72 fixing the procedure for implementing Regulation No 1408/71, in the version amended and updated by Regulation No 118/97, must be interpreted as meaning that, in a situation in which one of the parents is employed in a Member State other than the Member State of residence, for the purpose of calculating the supplementary allowance to which a migrant worker may be entitled in his or her Member State of employment, it is not possible to take account of all the family benefits received by the worker’s family under the legislation of the Member State of residence where, subject to verifications to be carried out by the referring court, the allowance for bringing up a family provided for under the legislation of the Member State of residence is not a benefit of the same kind, within the meaning of Article 12 of Regulation No 1408/71, as the family allowances provided for under that legislation, or the family allowances provided for by the legislation of the Member State of employment.

While the family benefits provided for by the legislation of the Member State of employment and those received by a worker or his or her family members under the legislation of the Member State of residence are intended, in accordance with Article 1(u)(i) of Regulation No 1408/71, to meet family expenses, they do not necessarily all have the same specific object or the same characteristics or recipients.

Moreover, only some of those benefits constitute family allowances within the meaning of Article 1(u)(ii) of Regulation No 1408/71.

In order for the overlap rule in Article 10(1)(b)(i) of Regulation No 574/72 to be applicable, it is necessary, for the purpose of calculating the supplementary allowance to which a migrant worker may be entitled in the Member State of employment, to identify, among the various family benefits that worker is entitled to under the legislation of that State and those received by the worker or his family members under the legislation of the Member State of residence, those which are ‘of the same kind’ within the meaning of Article 12 of Regulation No 1408/71, by reference to their object, purposes, the basis on which they are calculated, the conditions for granting them and the persons entitled to such benefits.

Moreover, in order for it to be concluded in any particular case that there is an overlapping of rights to family benefits, it is not enough, for example, for such benefits to be payable in the relevant child’s Member State of residence and, at the same time, to be merely potentially payable in another Member State where one of the parents of that child works, it being necessary for the person concerned to fulfil all the conditions, as to both form and substance, imposed by the domestic legislation of that State in order to be able to exercise that right.

(see paras 58-61, 73, 74, 76, operative part)