Saint-Leonard was amalgamated into the
City of Montreal in 2001, and Bissonnet was elected as one of the community's three representatives to the
Montreal city council in
that year's municipal election. The Montreal Island Citizens Union won a majority on council, and Bissonnet supported new mayor
Gérald Tremblay's administration. She was deputy mayor from January to April 2002, from September to December 2002, and again from May to August 2003, and served on the
Montreal Transit Corporation. She was re-elected in the
2005 municipal election also served as interim borough mayor of Saint-Leonard in 2008, following Zampino's resignation. In 2005, Bissonnet introduced a resolution at a meeting of the Saint-Leonard borough council to approve a twenty-year contract for the
Dessau subsidiary Sogep to manage the community's parks, pavilions, and tennis courts. The resolution was approved. In 2009, the
Montreal Gazette reported that Saint-Leonard was paying $1.06 million more under this arrangement than under its previous contract. Bissonnet did not seek re-election in 2009. ==Electoral record==