The provisions of Article 706-58 do not apply if, in view of the circumstances in which the offence was committed or the personality of the witness, knowledge of the identity of the person is essential for the exercise of the rights of the defence.
The accused may, within ten days of being informed of the content of a hearing conducted under the conditions of Article 706-58, contest the use of the procedure provided for in that Article before the president of the investigating chamber. The President of the Investigating Chamber shall give a reasoned decision, which may not be appealed, in the light of the documents in the proceedings and those in the file referred to in the second paragraph of Article 706-58. If it considers the challenge to be justified, it orders the hearing to be cancelled. It may also order that the identity of the witness be revealed provided that the witness expressly states that he or she accepts the lifting of his or her anonymity.