Marie Cossette's practice focuses on professional liability, public law, administrative law, and disciplinary law. She is regularly called to work on cases involving government relations in various forms. She has extensive experience relating to public inquiries (Chamberland Commission, Charbonneau Commission, Johnson Commission, Gomery Commission, and Poitras Commission) and recently served as counsel for the coroner's office during the public inquiry into a fire at the Résidence du Havre in L'Isle-Verte, Québec. She acted as independent counsel for the Canadian Judicial Council during the public inquiry into the conduct of the Honourable Michel Girouard. Her practice involves also business and construction law as well as product liability. Through her work in these two areas of practice, she has acquired extensive experience with issues involving ethical questions, professional conduct, and integrity, particularly in the field of construction. She has experience managing media relations during media crisis management and court cases. She also has practical knowledge of the workings of the print, television, and radio media and regularly serves as a legal analyst for the Réseau de l'Information (RDI) and Société Radio-Canada.