What steps can I take as a Dutch shareholder if I suspect a board member's conflict of interest breached the Corporate Governance Code?

General meeting rights. You can use the general meeting to ask questions, request explanations about any conflict of interest or related-party benefit, and exercise your voting rights. Depending on the articles of association and the allocation of powers, this can include decisions on the appointment, suspension, or dismissal of directors, and the approval of matters reserved to shareholders.
Ondernemingskamer (Enterprise Chamber). If there are well-founded reasons to doubt proper management, shareholders who meet the statutory threshold (sometimes alone, often together with other shareholders) can start an inquiry procedure. In urgent situations, you can also request immediate interim measures, such as suspending or appointing directors, to stabilize governance.
Claims and liability. Director liability claims are typically pursued by the company itself rather than by an individual shareholder, unless you suffered personal and separate damage. Often, the practical route is to push the company to act via shareholder governance tools or the Enterprise Chamber route.
Legal representation. You do not need a lawyer to exercise general meeting rights.
Court proceedings, including proceedings before the Ondernemingskamer, generally require Dutch legal representation (a Dutch advocaat) in practice.
Good luck!
Tom Meevis
Attorney-at-law at Law & More