A remark beforehand: For years I have been translating a variety of documents into English or Polish and certifying them in accordance with my official status as a sworn-in translator at the Frankfurt am Main District Court. I do not know of any case in which a certified translation issued by me would not be honoured outside Germany. You should always keep in mind however that translations as well as official copies of documents issued by German authorities may not be accepted abroad. In many cases it is necessary to provide an apostille for the document, which confirms the authenticity of the signature or the function of the person certifying the document for their use abroad. States that are not signatory to the Apostille Convention usually require a certification by means of legalisation. You will find more information on this here.
Better safe than sorry
Contrary to common belief, it is not certain that a certified translation will be accepted in another EU state, as this issue has not yet been resolved on a European level. This means that the legal status of translators and interpreters depends solely on each member-state's legislation. Therefore, for instance, German authorities do not accept any translations that have been certified abroad. Consulates of the Republic of Poland in Germany do not accept translations certified by German-sworn translators. On the other hand, German certifications are usually acceptable with British or US authorities, where there are to all intents and purposes no court-appointed translators.
Depending on the language mix, you can find more conflicting examples. As such, you would be well-advised to ask about the conditions required by the individual foreign authority to which you must submit certified translations. Should you have contact with the appropriate foreign authority, be it a ministry, university or corporation, then feel free to direct them towards my website and ask whether my qualification as a state-certified and sworn-in translator at Landgericht Frankfurt will be recognised.