All of the mentioned forms require notarial services. In the case of a private deed with a certified signature, parties may assemble the agreement themselves, or be assisted by a professional, and the notarial service consists of certifying the signature of the seller.
The same is true in the case of an authenticated private deed, with the distinction that the agreement has to be assembled according to a more formal set of rules regarding form. Authentication itself makes the notary liable for the content. The mentioned liability is a safety valve because the notary will deny service of authentication unless an adequate intervention into the content is permitted, assuring a proper level of legal certainty regarding form and content.
An authenticated private deed produces same legal effects as an authentic instrument (notarial act).
An authentic instrument (notarial act) is assembled directly by the notary making him/her liable for the content.
Further to different legal heritage and tradition within the same legal frame, certain modalities are more accepted in some regions of Croatia than others (notarial acts being especially accepted in the north-western coastal region of Croatia - Istria.)