The march was planned by the local Chamber of Commerce to show solidarity with the plant's employees, many of whom are opposing the closure of Gentilly-2.
Employees and supporters walked from City Hall and ended the walk in front of the power plant around noon.
The Quebec government made the decision to close the nuclear plant when the Parti Québécois came to power on Sept. 4.
On Saturday, Le Devoir, a French-language newspaper, reported that provincially owned Hydro-Québec concluded the revival of Gentilly-2 was not justified in its financial plan.
A report by Hydro-Québec states rebooting the plant would cost $2.4 billion more than the 2008 assessment. The price of electricity created would then cost 9.7 cents for every kilowatt per hour. This is in comparison to the 6.2 cents expected for the La Romaine central being built in northern Quebec.
A union representing about half of the 700 employees at the station has been opposing the closure.
Hydro-Québec has issued a notice saying the plant will be closing.