La. Civ. Code art. 1849
Current with operative changes from the 2024 Third Special Legislative Session
In all cases, testimonial or other evidence may be admitted to prove the existence or a presumption of a simulation or to rebut such a presumption. Nevertheless, between the parties, a counterletter is required to prove that an act purporting to transfer immovable property is an absolute simulation, except when a simulation is presumed or as necessary to protect the rights of forced heirs.
La. C.C. § 1849