B-1, r. 3.1 - Code of Professional Conduct of Lawyers

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65. A lawyer may communicate confidential information in the following situations:
(1)  with the express or implied authorization of the client;
(2)  if an express legal provision orders or authorizes him to do so;
(3)  in order to collect his unpaid fees before a tribunal;
(4)  in order to defend himself in the event of proceedings, complaints or allegations calling his professional competence or conduct into question; or
(5)  to identify and resolve conflicts of interest arising from a change of firm by a lawyer or from changes to the composition or ownership of a firm, but only if the information necessary for this purpose, namely, the names of current and former clients and the summary nature of the mandates entrusted by such clients, will not jeopardize professional secrecy or if doing so will not result in prejudice to such clients;
(6)  in order to prevent an act of violence, including a suicide, where the lawyer has reasonable cause to believe that there is an imminent danger of death or serious bodily injury to a person or an identifiable group of persons.
O.C. 129-2015, s. 65.