A German national who applies for and receives a foreign nationality (except the nationality of one of the EU Member States or Switzerland) loses his/her German nationality. The only way of preventing the loss of German citizenship is if the applicant obtained permission to retain the nationality by the German authorities prior to acquiring the foreign nationality.
German nationals required to perform military service who voluntarily enter the forces or comparable armed groups of a country of which they are also a national without the consent of the district draft board lose their German nationality automatically.
For further advice, please contact the competent German mission covering your place of residence.
German missions abroad: Countries A to Z