Short answer. Under Article 713 of the Civil Code, property acquired by occupation includes wild animals taken by hunting or fishing, hidden treasure, and abandoned movables. These are things that are appropriable by nature — capable of being privately owned — but currently without an owner.
What the law says
Things appropriable by nature which are without an owner, such as animals that are the object of hunting and fishing, hidden treasure and abandoned movables, are acquired by occupation.
Civil Code, Article 713 — Acquisition By Occupation. Read the full provision →
The two requirements for occupation
Article 713 of the Civil Code sets out two conditions that a thing must satisfy before it can be acquired by occupation. First, it must be appropriable by nature — that is, by its character, it is the kind of thing capable of being owned privately. Not everything can be appropriated: things reserved for public use or classified as property of the State fall outside this category. Second, the thing must be without an owner at the moment of taking. An item that already has an owner cannot be acquired this way, regardless of how it is found.
Animals taken by hunting and fishing
Wild animals — those living free in their natural habitat — are the clearest example Article 713 provides. A person who hunts or fishes acquires ownership of the animals taken through the act of capture. At the moment of taking, those animals had no private owner; the act of occupation creates ownership. Note that this applies to animals in the wild, not to domesticated animals or those that have escaped from an owner but can be identified and reclaimed. Hunting and fishing rights are also subject to applicable special laws and regulations.
Hidden treasure
Hidden treasure — valuables that have been concealed or unknown for so long that the owner can no longer be identified — is another category the Civil Code includes within occupation. The rules on how hidden treasure is divided between the finder and the landowner are addressed in separate articles of the Civil Code. Article 713 establishes only the foundational principle: hidden treasure belongs to the category of things without an owner and can therefore be acquired. The identity of the landowner, the circumstances of discovery, and the nature of the treasure each affect how ownership is ultimately allocated.
Abandoned movables
A movable that an owner has voluntarily abandoned — intending to give up ownership — reverts to having no owner and may be acquired by occupation. Abandonment requires both the physical act of giving up possession and the intention to relinquish ownership. Lost property is different: loss is involuntary, and a lost item still has an owner. Whoever finds lost property is obligated to return it or report it; taking it with intent to keep is not occupation under Article 713 but something the Code treats differently. The distinction between abandonment and loss determines whether the finder acquires ownership or incurs an obligation.