Code of Organization and Civil Procedure (Cap. 12), article 590

590. (1) It shall be in the discretion of the court to determine, in each particular case, when a witness is not bound to answer a particular question on the ground that the answer to such question might tend to expose his own degradation, or when a witness will not be compelled to give evidence as to facts the disclosure of which will be prejudicial to the public interest. Privilege as to facts known ratione officii. (2) No witness may be compelled to disclose any information derived from or relating to any document to which article 637(3) applies. Person present at trial may not be produced as witness. Discretionary power of court.