Short answer. Yes. Article 1602 of the Civil Code states that in cases where a sale is deemed an equitable mortgage, any money, fruits, or other benefit received by the buyer as rent or otherwise shall be considered as interest subject to the usury laws. This applies automatically — not by agreement.
What the law says
any money, fruits, or other benefit to be received by the vendee as rent or otherwise shall be considered as interest which shall be subject to the usury laws
Civil Code, Article 1602 — When a Sale Is Really a Mortgage. Read the full provision →
What Article 1602 does
Article 1602 of the Civil Code identifies six situations in which a contract that looks like a sale is presumed to be an equitable mortgage — that is, a transaction whose real purpose is to secure a debt rather than to transfer ownership. The six indicators include: an inadequate price, the vendor remaining in possession, extensions of the redemption period, the buyer retaining part of the purchase price, the vendor paying taxes on the sold property, and any other facts showing the real intent is to secure a debt. In any of these cases, the article adds a critical consequence: any money, fruits, or other benefit to be received by the vendee as rent or otherwise shall be considered as interest.
Why rent becomes interest
When a 'sale' is really a mortgage in disguise, the buyer who receives rent from the seller-occupant is in the economic position of a lender collecting returns on a loan. The sale price functions as the loan principal; the rent or fruits of the property function as the lender's return. Article 1602 recognizes this economic reality and classifies those receipts as interest — not income from a property ownership arrangement. This classification then brings the interest rate into question under the usury framework, which regulates how much interest a lender may lawfully charge.
The six indicators of an equitable mortgage
Each of the six indicators listed in Article 1602 reflects a situation where the formal structure of a sale diverges from economic reality. An unusually inadequate price suggests the seller needed emergency funds and accepted below-market terms. Remaining in possession as lessee means the 'seller' never really gave up the property. Extensions of the redemption period suggest an ongoing debt relationship. The buyer retaining part of the price suggests a loan advance structure. Seller paying taxes indicates the seller still considers themselves the real owner. And the catch-all sixth clause covers any other arrangement that achieves the same economic purpose.
Practical significance for sellers who remained in possession
If you 'sold' your property but continued living in it as a lessee, and you are trying to recover the property, the equitable mortgage doctrine may be your avenue. If the transaction exhibits the markers in Article 1602, a court may characterize it as a mortgage rather than a sale — which means the 'buyer' is a mortgagee, not an owner, and the transaction can be challenged on the basis of the actual debt and the interest the 'buyer' has been collecting. The rents paid during the period of possession may then be reclassified and credited against the principal. Speaking with a lawyer about the specific facts of your transaction is the necessary first step.