In March 2019, the Constitutional Court had to consider whether the obligation for lawyers to file an annual listing of clients who are taxable for VAT purposes with the tax authorities, is compatible with the duty of professional secrecy. Such listing discloses the identity of clients with whom the lawyer has carried out transactions for a total amount exceeding EUR 250 to the authorities. The Constitutional Court held that the duty of professional secrecy does not prevent such filing because the information filed does not concern the core activities of lawyers; it is not related to confidential information disclosed by a client that is potentially incriminating.

On 24 September 2020, the Constitutional Court partially annulled the Anti-Money Laundering Act of 18 September 2017 (AMLA) based on legal privilege. Under the AMLA, lawyers were obliged to report any suspicion of money laundering or terrorist activities by clients to the Financial Intelligence Processing Unit (CFI), even when the client had withdrawn the suspicious transaction, following the advice of the lawyer. The Constitutional Court held that in such case, the reporting obligation conflicts with the duty of professional secrecy of lawyers because the information received is covered by legal privilege and therefore annulled this aspect of the reporting obligation. This annulment was extended to reporting obligations of employees of lawyers, because no person external to the relationship between the lawyer and their client should ever be obliged to report legally privileged information to the CFI.

The Supreme Court clarified the scope of application of the duty of professional secrecy with respect to information not received directly by lawyers from a client, in its judgment of 19 October 2021. The Supreme Court held that an (oral) conversation between the lawyer of a defendant in criminal proceedings and another co-defendant, which revealed incriminating information regarding the lawyer's client, is covered by the duty of professional secrecy of that lawyer. The content of such a conversation may therefore not be intercepted during investigations or used in legal proceedings.

Finally, the Court of Appeal in Ghent confirmed on 3 February 2020 that the duty of professional secrecy applies regardless of the medium on which the information was communicated. If a communication technique is used which allows information to be consulted by third parties, legal privilege will only lapse if the information is also addressed to third parties. In particular, any communication sent to the professional email address of a client, which may from a technical point of view be accessed by its employer, still falls under the duty of professional secrecy. This is also the case if the accessing party is a counterparty in legal proceedings.