Grosso modo, the Land Registrar has a rather passive role: he or she can only verify if the document is indeed a document that could be entered in the land register (i.e. a notarial act or an official act) and if the document contains indeed a juridical act that can be entered in the land register (i.e. an act inter vivos of constitution or transfer of a property right). If the presented document is not acceptable, it is rejected.
The decision of the Land Registrar could be appealed to the civil judge. This is extremely rare.