Simon's practice covers various fields of commercial litigation, including class actions, insurance disputes, professional malpractice, and post-closing disputes. In addition to regular civil proceedings, he represents clients in obtaining, or defending against, injunctions, seizures before judgment, and other extraordinary proceedings. In the course of his practice, he regularly appears before courts and administrative tribunals in Québec, including for several trials and class actions. Simon also advises corporations and individuals in relation to regulatory or criminal matters, such as anti-corruption, competition, securities, or financial matters. In this context, he advises clients in responding to search warrants and investigations by government authorities or in conducting internal investigations. He also defends clients in enforcement proceedings brought by government authorities and self-regulatory organizations, including public prosecutors and securities regulators. Simon has advised national and international corporations on various matters dealing with dispute avoidance and resolution and with compliance with the penal provisions of statutes in Québec and Canada.