British Prime Minister David Cameron, German Chancellor Angela Merkel and other European leaders will join French President Francois Hollande at the rally.
Italian Prime Minister Matteo Renzi, Spanish Prime Minister Mariano Rajoy and Finnish Prime Minister Alexander Stuff have sent Tweets saying they will be there.
Michel Robitaille, Quebec's delegate-general in the French capital will attend on behalf of the province.
And French citizens in Ottawa are organizing a Sunday afternoon rally here, near Parliament Hill.
Prime Minister Stephen Harper has spoken with Hollande to offer Canada's condolences on the brutal attacks.
Harper commended French authorities on their handling of two hostage-taking incidents on Friday, officials said.
Two gunmen blamed for the murder Wednesday of a dozen people at the offices of a satirical magazine in Paris were killed in one of these incidents. Another gunman was killed in a separate incident which also left four hostages dead.
Harper told Hollande that Canada stands with France as it mourns.
He said Canada and its allies will not be intimidated.
The two leaders condemned the attacks and spoke of the importance of co-operating to counter the scourge of extremism and terrorism.
Shimon Koffler Fogel, CEO of the Centre for Israel and Jewish Affairs, the advocacy agent of the Jewish Federations of Canada, also offered condolences.
"These acts of terror represent not only an attack on the people of France or the targeting of the French Jewish community; they constitute an assault on fundamental western and democratic values," he said.
While the two brothers who carried out the massacre on Wednesday said they sought martyrdom, Fogel branded them as criminals:
"They will not dictate our values. These individuals represent a perversion of Islam, and we must continue to work in mutual co-operation and respect with the Muslim community to prevent the influence of distorted ideology and propaganda masquerading as religion."
Liberal Leader Justin Trudeau also labelled the gunmen as criminals.
He expressed condolences for the families and friends of the victims.
"We offer our deep and sincere gratitude to the brave law enforcement personnel who have selflessly and courageously sought to bring an end to this terrorism."
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