Three masked gunmen stormed the offices of satirical weekly newspaper Charlie Hebdo on Wednesday, killing 10 journalists and two police officers. Another 20 people were injured, including four critically, in the shooting.
"Our first thoughts are with the victims, their families and the people of France," Couillard said in a statement.
"Our ties with France and the French are profound, sincere and historic. We share not only a common language, but also values of liberty and democracy. On behalf of all Quebecers, I express my condolences and salute their courage during this difficult time."
The flag at the National Assembly in Quebec City was lowered to half mast.
Parti Québécois interim leader Stéphane Bédard also offered his condolences, telling reporters the shooting represented an attack on journalism, one of the pillars of democracy.
François Legault, head of the Coalition Avenir Québec, came under hot water on Twitter for making light of the news. He suggested a character from the popular TV show Homeland should pursue the attackers.
He later sent out a statement condemning what he called a "barbaric act."
Freedom of expression
While it remains unclear what prompted the attacks, one Montreal Muslim leader said certain depictions of the Prophet Muhammad in Charlie Hebdo went too far.
Salam Elmenyawi, president of Muslim Council of Montreal, argued the cartoons would qualify as hate speech under Canadian law.
Elmenyawi called the shooting “very sad,” but said there should be “certain limits when it comes to religion, and attacks on religion, that may harm social fabrics and societies in general.”
"Of course we respect very much freedom of expression, but there are certain limits when it comes to religion," he said in an interview.
“Satire is sometimes much more effective even in insulting a community than any other method. This kind of method can be very, very serious because it can cause psychological damage to a community.”
He said Muslims would feel offended if any prophet — not only Muhammad, but also Jesus, Abraham, or David — were depicted negatively.
Djemila Benhabib, a former PQ candidate and an outspoken critic of religious extremism, was friends with one of the victims.
She described Stéphane Charbonnier, better known under his cartoonist name of Charb, as a man of courage.
She said he would want people to continue to talk, write and draw about religious extremism.