1. In your legal system, are there acts which fall within the notion of an authentic instrument as defined in the European Union legislation?<br>[‘authentic instrument’ means a document which has been formally drawn up or registered as an authentic instrument in a Member State and the authenticity of which:<br>(i) relates to the signature and the content of the authentic instrument; and<br>(ii) has been established by a public authority or other authority empowered for that purpose by the Member State of origin.]

Yes.

If so, what are they? Are these only notarial acts or also acts of other authorities?

According to Article 432 et seq. of the Code of Civil Procedure and Article 158 of the Civil Code and Article 8 of the Hellenic Code of Notaries, documents certifying the date, place and authenticity of the parties’ wishes and signed by the parties or the person before the notary and also by the notary are considered authentic instruments.
Article 432 et seq. of the Code of Civil Procedure defines an authentic instrument as an instrument which has been issued, with the required formalities, by a public officer-holder having competence and capacity to act.

These are therefore documents issued by notaries or bailiffs, but also by courts, mayors, civil registrars, etc.