Oral testimony has always been taken up as an element of evidence in the French criminal proceedings. However considered as unreliable because human, it hasn't ceased to be the subject of critics, lately revived with the emergence of scientific proof within contemporary penal trial. This statement is based on the anachronistic postulate that oral testimony, considered through the only view of the witness as defined by the procedural rules, is unity, whereas indeed it does present a dual character. The probationary value of oral testimony is suffering from this lack or recognition and its necessity within criminal procedure is also being questioned when there should be no hesitation whatsoever with regard to its use. In fact, oral testimony is not just a useful element of proof when trying to establish the truth, it does also illustrate and strengthen the governing principles of penal trial such as promulgated by the French legislator and the European convention of Human Rights.