In the cases provided for in articles 56-1 and 56-1-1, without prejudice to the prerogatives of the President of the Bar or his delegate as provided for in Article 56-1 and the rights of the person searched as provided for in Article 56-1-1, the professional secrecy of counsel may not be invoked against investigation or enquiry measures when these relate to the offences mentioned in Articles 1741 and 1743 of the General Tax Code and articles 421-2-2, 433-1, 433-2 and 435-1 to 435-10 of the Criminal Code as well as the laundering of these offences, provided that the consultations, correspondence or documents held or transmitted by the lawyer or his client establish proof of their use for the purposes of committing or facilitating the commission of the said offences.