Short answer. Yes. Article 1195 of the Civil Code provides that anything paid or delivered before the arrival of the period, where the obligor was unaware of the period or believed the obligation was already due, may be recovered with the fruits and interests. So the recovery includes any interest the payment earned.
What the law says
Anything paid or delivered before the arrival of the period, the obligor being unaware of the period or believing that the obligation has become due and demandable, may be recovered, with the fruits and interests
Civil Code, Article 1195 — Premature Payment. Read the full provision →
What Article 1195 provides
Article 1195 of the Civil Code addresses exactly this situation: "Anything paid or delivered before the arrival of the period, the obligor being unaware of the period or believing that the obligation has become due and demandable, may be recovered, with the fruits and interests." The article does not limit recovery to the bare amount paid — it expressly extends it to whatever fruits and interests came from that payment.
Why fruits and interest are included
The phrase "with the fruits and interests" exists because the creditor was not entitled to hold the payment at all before the period arrived. If the money sat with the creditor and earned interest, or if property delivered produced fruits, those gains exist only because the creditor had something it should not yet have had. Returning the bare principal without what it earned would leave the creditor better off for having received a payment it was not yet owed.
The recovery is tied to being unaware or mistaken
Article 1195 conditions this recovery on the payer's state of mind at the time: the obligor must have been "unaware of the period or believing that the obligation has become due and demandable." That description fits someone who pays early by mistake, not knowing the debt was not yet due, or wrongly believing it already was. The article is written around that specific situation, and it is what your question describes.
Applying this to your situation
Because you paid off the loan early by mistake, before it was actually due, your situation matches what Article 1195 describes. If you recover the payment, the article entitles you to recover it together with the fruits and interests it produced while the creditor held it — not just the bare amount you originally paid. The recovery is meant to put you back where you would have been had the premature payment never happened, rather than leaving the creditor with a windfall from money it should never have received early.