Short answer. Possibly. The Civil Code allows a partition, whether judicial or extra-judicial, to be rescinded for lesion when a co-heir received things worth at least one-fourth less than the share they were entitled to, measured by the value of those things at the time they were adjudicated.
What the law says
A partition, judicial or extra-judicial, may also be rescinded on account of lesion, when any one of the co-heirs received things whose value is less, by at least one-fourth, than the share to which he is entitled, considering the value of the things at the time they were adjudicated.
Civil Code, Article 1098 — Rescission for Lesion. Read the full provision →
"Lesion" means a measurable shortfall, not a general complaint
Article 1098 does not let every heir who feels shortchanged reopen a partition. It sets a specific threshold: rescission is available where a co-heir received things whose value is less, by at least one-fourth, than the share to which he is entitled. A modest imbalance, or a division you simply regret with hindsight, does not clear that bar. What the article targets is a partition where the numbers themselves, once actually compared, show a gap of a quarter or more between what you got and what you were owed.
Both judicial and extra-judicial partitions are covered
The article applies whether the estate was divided by a court proceeding or by the heirs' own extra-judicial agreement — judicial or extra-judicial — so a family settlement is not automatically insulated from this remedy just because no court was involved in dividing the property. What matters is the substance of the shortfall, not the procedural path the partition took to get finalized.
The valuation point is fixed in time
The comparison is made considering the value of the things at the time they were adjudicated — the moment the partition assigned specific property to each heir. A parcel that later gains value, or a business interest that later loses it, does not retroactively create or erase lesion; what is measured is whether the shares were fairly proportioned against each other as of that adjudication. This is why documenting values at the time of partition, not years afterward, is what actually supports a claim under this article.
What to gather if you think you were shortchanged
Start by reconstructing, as precisely as you can, what each heir's share should have been and what each heir actually received, valued as of the partition. Appraisals, tax declarations, or sale records from around that time are the kind of evidence that turns a general sense of unfairness into the specific one-fourth showing the article requires. Because the deficiency has to be measurable, a rough impression that "my sibling got more" is not enough on its own — the figures have to add up to the threshold.