Premier Philippe Couillard is calling out the Quebec City residents who booed the prime minister as he spoke in English during a Fête Nationale event.

Justin Trudeau was in the provincial capital for the opening of a new wing of the city's fine arts museum, timed to coincide with the provincial holiday associated with the celebration of francophone culture in Quebec.

During a speech at the unveiling, Trudeau addressed the results of Thursday's referendum in the United Kingdom, which saw voters support leaving the European Union.

As Trudeau switched from French to English, a round of boos and whistles erupted in the crowd. Trudeau continued speaking in English for several seconds before switching back to French.

The crowd cheered when Trudeau returned to speaking French.

Couillard, who also attended the opening, was asked about the booing at a news conference later.

"It's unfortunate," the premier told reporters. "We could have listened to his message in a more positive way."

"It's the Fête Nationale of all Quebecers, we expect that the speeches are given in French. He wanted, I think, to address all Canadians about the Brexit issue. But I think we have to remind everyone that we have to be open and tolerant."