The notary verifies the ownership but does NOT analyze: if it can be built, if the constructions are legal, if there are problems with boundaries, cadastre-registry discordances, sectorial affectations, etc. A specialized lawyer performs complete due diligence that can prevent you from buying serious problems. The investment in advice (800-1,500€) is tiny compared to the risk of buying a property with problems (which can cost tens of thousands of euros to solve or make the property unsaleable).