An apostille is an additional confirmation of authenticity of a foreign document. Here, an apostille confirms the authenticity of the signature and, if applicable, the seal of the signatory, as well as their authority to issue the document.
However, the 1969 Treaty on the Waiver of Legalization of Documents between Germany and Italy applies. Accordingly, public documents bearing an official seal or stamp do not require legalization, authentication or apostille for use in the respective other country. This also applies to documents issued by consular or diplomatic missions.