Expired or lost passports – Germany
Whilst you should avoid travelling with expired documents, if you have German nationality, you may travel on an expired passport to countries that have signed and ratified the Council of Europe Convention as long as the passport has not been expired for more than one year. However, you will need to have an official national ID card which is either still valid or which has been expired for less than one year.
If you are a national of another EU country which has signed and ratified the Convention, you may travel to Germany as long as you have one of the documents listed under your country in the annex to the Convention.
The website of the Germande has information on passport requirements and consular help if you lose your passport.