Short answer. Yes. Money or property an illegitimate child received from a parent during that parent's lifetime is charged to the child's legitime, meaning it counts as an advance and is deducted from the share due at the parent's death. If the gift exceeded what could be freely given, it is reduced.
What the law says
Donations which an illegitimate child may have received during the lifetime of his father or mother, shall be charged to his legitime.
Civil Code, Article 910 — Donations Charged to the Legitime. Read the full provision →
A lifetime gift is treated as an advance, not a bonus
The idea behind the rule is fairness among heirs. A parent who hands a child money, a lot, or a vehicle while still alive has, in the eyes of the law, already begun paying that child's inheritance. So when the estate is settled the value of what was given is added back to the estate for the purpose of computing shares, and then deducted from that child's own legitime. The child is not punished; the child simply cannot be paid twice. The same logic applies to legitimate children under a companion provision. What the rule does not do is turn the gift into a debt: if the advance was smaller than the legitime, the child still collects the balance.
Read this article with the Family Code, not on its own
The wording of this provision dates from 1950, when the Civil Code sorted illegitimate children into several sub-classes with different shares. That classification no longer exists. The Family Code, which took effect in 1988, now governs: it recognises a single class of illegitimate child, and it fixes the legitime of each illegitimate child at one-half of the legitime of a legitimate child. Except for that change, the Civil Code's rules on successional rights continue to apply, which is why the charging rule above is still live law. So when you compute what the child was owed, use the Family Code share, not any older fraction you may find quoted in the Civil Code text.
When the gift was too big
If the donation exceeds the portion the parent could freely dispose of, the law calls it inofficious and it is reduced so that the other heirs' legitimes are restored. That is an arithmetic exercise, not a moral one. The property is valued, added to whatever the parent still owned at death, debts and charges are subtracted, and each heir's legitime is computed on that figure. Only then can anyone say the illegitimate child received more than the law allowed. A common mistake is to look at the gift alone and declare it excessive; a gift that looks enormous may still fit comfortably inside a large estate.
What this does not settle
The rule assumes filiation is established. If the child's status as the parent's child is itself disputed, that has to be resolved first, and it is a separate and often harder question. The article also says nothing about whether the transfer was validly made — donations of land carry their own formal requirements — nor about gifts that were really payments for services or reimbursements rather than donations. Finally, reduction does not happen by itself: an heir who believes the legitimes were invaded must raise it in the settlement of the estate, with the deed, the valuation, and an inventory to back it up.