Marsan was first elected in Robert-Baldwin in 1994 and was in charge of the electoral campaign program Pour un Quebec en Santé in 1998.
He was re-elected for a fourth term in 2007 and named the Parliamentary Secretary to the Minister of Immigration and Cultural Communities.
On September 16, 2013, a journalist revealed a letter circulating in the Association sépharade de la banlieue ouest de Montréal signed by Pierre Marsan and his chief electoral officer, Aimé Bensoussan.
[1] The Parti québécois and the Coalition Avenir Québec strongly reacted to the event, claiming that this added to a long list of recent instances of corruption within the Quebec Liberal Party, which has favoured Liberal contributors in daycare permit attributions and other types of financial compensations.
[2] On September 17, 2013, the Chief Electoral Officer of Quebec, Jacques Drouin, declared that there would be an inquiry in the constituency of Robert-Baldwin following these events, upon which Pierre Marsan and Aimé Bensoussan would be called.