Marc is a lawyer, and chaired a national government-industry task force on the residential renovation industry. He conducted three program reviews at UNESCO. He retired from the Senior Management Group of Ontario’s Ministry of the Attorney-General (at Ontario Municipal Board, now Ontario Land Tribunal), where he wrote over 800 decisions. He authored the book The Canadian Home, and over 250 other works published in seven languages; two short books were distributed by the International Union of Local Authorities and the World Bank.