See - http://sc.judiciary.gov.ph/jurisprudence/2012/december2012/162930.pdf
"x x x.
Can the receipt dated October 23, 1972 evidencing sale of real property, being a private document, be a basis of petitioner's claim over the
subject property?
Article 1358 of the Civil Code provides that acts and contracts which have for their object the transmission of real rights over immovable
property or the sale of real property must appear in a public document. If the law requires a document or other special form, the contracting parties may compel each other to observe that form, once the contract has been
perfected.
In Fule v. Court of Appeals, the Court held that Article 1358 of the
Civil Code, which requires the embodiment of certain contracts in a public
instrument, is only for convenience, and registration of the instrument only adversely affects third parties. Formal requirements are, therefore, for the benefit of third parties.
Non-compliance therewith does not adversely Art. 1358. The following must appear in a public document:
(1) Acts and contracts which have for their object the creation, transmission, modification or extinguishment of real rights over immovable property; sales of real property or of an interest therein a governed by Articles 1403, No. 2, and 1405;
(2) The cession, repudiation or renunciation of hereditary rights or of those of the conjugal partnership of gains;
(3) The power to administer property, or any other power which has for its object an act appearing or which should appear in a public document, or should prejudice a third person;
(4) The cession of actions or rights proceeding from an act appearing in a public document.
All other contracts where the amount involved exceeds five hundred pesos must appear in writing, even a private one. But sales of goods, chattels or things in action are governed by Articles, 1403, No. 2
and 1405. (Emphasis supplied.)
However, in this case, the trial court dismissed petitioner's complaint
on the ground that the receipt dated October 23, 1972 (Exhibit “B”) is a
worthless piece of paper, which cannot be made the basis of petitioner’s
claim of ownership over the property as Mr. Arcadio Ramos, an NBI
handwriting expert, established that the signature appearing on the said
receipt is not the signature of respondent Beatriz Miranda. The Court of Appeals affirmed the trial court's dismissal of the complaint.
The Court sustains the decision of the Court of Appeals.
x x x."
