Short answer. Just his share, unless the will says otherwise. Article 929 provides that where the testator owned only a part of or an interest in the thing given, the legacy is limited to that part or interest — unless he expressly declared he was giving the thing in its entirety. Silence means you take only what he owned.
What the law says
If the testator, heir, or legatee owns only a part of, or an interest in the thing bequeathed, the legacy or devise shall be understood limited to such part or interest, unless the testator expressly declares that he gives the thing in its entirety.
Civil Code, Article 929 — Partial Ownership. Read the full provision →
What Article 929 provides
Article 929 provides that if the testator, heir, or legatee owns only a part of, or an interest in the thing bequeathed, the legacy or devise shall be understood limited to such part or interest, unless the testator expressly declares that he gives the thing in its entirety. The rule is common sense about what a testator can give: a person cannot dispose of more than he owns. If your father held only a share in a parcel — say a half, or an undivided co-ownership interest — a gift of 'the parcel' is read as a gift of his share in it, not of the whole thing.
Why the default is 'only his share'
The presumption protects the rights of the other owners. Where property is co-owned, the co-owners' shares are not the testator's to give, and the law will not read an ordinary bequest as an attempt to hand over what belongs to someone else. So the safe and default reading is the narrow one: the legacy carries only the interest the testator actually held. This spares the estate from promising the impossible and spares the other co-owners from a will that purports to dispose of their property. What you receive is exactly the slice your father owned, no more.
The exception: an express gift of the whole
The article leaves one door open — where the testator expressly declares that he gives the thing in its entirety. If the will plainly says he intends the legatee to have the whole thing, not just his share, that stated intention is honoured. But it triggers a different mechanism: since the testator cannot give what he does not own, giving the whole means the estate must acquire the other owners' shares, or pay their value, so the legatee ends up with the entirety. This only happens on an express declaration; it is never presumed from a plain gift of the property.
How to read your father's will
Start by finding out exactly what your father owned in the property at his death — full ownership, a fractional co-ownership share, or some lesser interest — because that, by default, is the measure of your gift. Then read the bequest for any express words giving you the thing in its entirety; without them, you take only his interest and become a co-owner alongside whoever else holds shares. If the will does declare the whole is meant for you, the estate must make that up from the other shares, a heavier obligation. The title documents and the will's exact wording together settle what you get.