++++ 1. Social security for migrant workers - Equal treatment - National rules making payment of a supplementary allowance to pensioners who are nationals of other Member States subject to a twofold condition regarding reciprocity under an international agreement and prior residence - Not permissible (Council Regulation No 1408/71, Art. 3(1)) 2. Member States - Obligations - Failure to fulfil Treaty obligations - Maintenance of national rules incompatible with Community law - Justification based on the existence of administrative practices ensuring that Community law is applied - Not permissible