La. Stat. tit. 13 § 3720
Any deed, counter letter, power of attorney, declaration, contract, or other instrument, under private signature, purporting to be attested by two or more witnesses and accompanied by an affidavit of the vendor or grantor that the same was signed or executed by him, or by an affidavit of one or more such witnesses, made at or after the signing and execution of such deed, counter letter, or other instrument, and setting forth substantially that the instrument was signed or executed by the party or parties thereto in the presence of the affiant or affiants, shall be deemed, taken and accepted, prima facie, and without further proof, as being true and genuine, and shall be so received and accepted in evidence in the courts of Louisiana, without further proof.
In the event that the instrument referred to in the above paragraph is executed outside of the State of Louisiana then the fact that the notary public is one of the witnesses to either the instrument itself or the attestation thereof or both shall not affect the validity or admissibility of the document as set forth in the preceding paragraph.
The provisions of this Section shall be deemed remedial and shall apply to all instruments heretofore executed and authenticated as well as to such instruments executed and authenticated subsequent to July 30, 1952.
La. R.S. § 13:3720