Short answer. You must collate half. Article 1066 of the Civil Code provides that when a parent gives a donation to a child's spouses jointly, the child is obliged to bring to collation one-half of the thing donated. The other half — your spouse's share — is not subject to collation.
What the law says
if they have been given by the parent to the spouses jointly, the child shall be obliged to bring to collation one-half of the thing donated.
Civil Code, Article 1066 — Donations to a Child's Spouse. Read the full provision →
The starting point: donations to a spouse are not collated
Article 1066 of the Civil Code opens with an important baseline: donations a parent gives to a child's spouse alone are not brought to collation. If your parent donated property exclusively to your husband or wife — not to you — that donation has no effect on your own share of the inheritance. The spouse receives it as an outsider to the succession, not as a compulsory heir, and the collation rules that apply to compulsory heirs simply do not reach the spouse's portion.
When the donation is to both spouses jointly
The rule changes when the parent donates to the child and the child's spouse together as a unit. Article 1066 provides that in that case, "the child shall be obliged to bring to collation one-half of the thing donated." The law treats the jointly donated property as split equally between the child and the spouse. Only the child's half — which the parent effectively gave to a compulsory heir — is subject to collation in the parent's estate. The spouse's half remains outside the collation calculation entirely.
Why only half is collated
Collation exists to ensure that compulsory heirs do not receive disproportionate advances on their inheritance at the expense of their co-heirs. A parent who gives to both a child and a non-heir spouse is partially making a donation to someone who has no claim on the estate's reserved share. The law draws a sensible line: only the part that benefits the compulsory heir counts toward what that heir has already received. The other half, attributed to the spouse, goes outside the succession accounting.
Practical implications at settlement
When the parent's estate is eventually settled and the legitimes are computed, you will need to account for half the value of any joint donation your parent made to you and your spouse. If that half, combined with other donations you received, approaches or exceeds your proportionate share of the estate, it may affect how much you receive from the estate — or trigger a reduction of the donation if it was inofficious. Knowing that only half is collated — not the full amount — can significantly change that computation, which is why the precise wording of the donation instrument matters.