Payments which a student, or an apprentice (including in the case of the Federal Republic of Germany a "Volontar" or a "Praktikant"), or trainee, who is or was immediately before visiting a Contracting State a resident of the other Contracting State and who is present in the first-mentioned state solely for the purpose of his education or training receives for the purpose of his maintenance, education or training shall not be taxed in that State, provided that such payments arise from sources outside that State.