On the day of Montreal’s big 375th anniversary celebrations, the Montreal police brotherhood has decided to air its grievances in a very public way.

The police union set up four billboards around the city designed to put the pressure on Mayor Denis Coderre.

With a smiling image of Coderre wearing a party hat and holding a party horn, the banner reads in French: "A mayor who has despised his police officers for the past three years, that’s worth celebrating."

The billboards were installed overnight on Viger Ave. W at the corner of de Bullion St., Saint-Laurent Blvd. at the corner of De Maisonneuve Blvd., on Highway 10 at the intersection of Highway 132, and – most notably – on the Montreal-bound side of the Jacques-Cartier Bridge.

Dignitaries and thousands of Montrealers are expected to gather Wednesday night for an illumination ceremony as the bridge is lit up for the first time.

In a statement issued Wednesday morning, the police union criticizes Mayor Coderre for his part in a contract dispute regarding pensions.

Police officers have been without a contract since December 31, 2014.

The union is also promising to protest Wednesday evening on the streets of Montreal.