++++ Social security for migrant workers ° Equal treatment ° National provision granting reimbursement of an employee' s contributions to a compulsory insurance scheme in the event of affiliation to a special scheme for civil servants ° Reimbursement not available for an employee who has become a civil servant in another Member State ° Permissible (Council Regulation No 1408/71, Arts 3, 9, 10(2) and 13(2)(d))