General Provisions
Every person has the right (subject to Section 37's restrictions) to defend their own or another's body against any offence affecting the human body, and their own or another's property (movable/immovable) against theft, robbery, mischief, or criminal trespass (or attempts at these).
This establishes the basic scope of the right to self-defence - covering both defence of one's own or someone else's physical body, and defence of one's own or someone else's property against specific property crimes.
This is why intervening to physically stop someone attacking a stranger, or to prevent a burglar from stealing property (even property that isn't yours), can be legally protected as private defence rather than treated as an offence.