Paul Desmarais, Sr. (born January 4, 1927, in Sudbury, Ontario) is a Canadian financier. He is also one of the ten richest persons in Canada and is considered to be one of the country's most powerful men.

Desmarais took control of his family's bus service, Sudbury Bus Lines, in 1951. He then acquired additional bus lines in the Ottawa area and Quebec City (including Quebec Autobus and Provincial Transport). By 1968, Desmarais's holding company, Trans-Canada Corporation Fund (TCCF), owned the bus line Provincial Transport, an interest in Toronto-based Imperial Life Assurance and Gesca Ltée, (which had an interest in the Montreal paper La Presse). That year TCCF made a share-exchange offer with Power Corporation of Canada, headquartered in Montreal, Quebec, whereby Paul Desmarais became Chairman and Chief Executive Officer.

Amongst its numerous worldwide holdings, Desmarais' Power Corporation of Canada owns about 15% of Groupe Bruxelles Lambert , one of Belgium's top ten companies which, in 2001 acquired a 25% interest in the German-based global publishing giant, Bertelsmann AG whose subsidiaries include Random House. Through his holdings, Paul Desmarais is also the largest shareholder of the giant French oil conglomerate, TotalFinaElf.

Desmarais has been publicly accused of having close business ties with Saddam Hussein, which Desmarais has refuted. His oil company, Total_S.A., made a deal with Saddam giving it exploration rights to 25% of Iraq's oil reserves. BNP Paribas, the bank which handled the money for the Oil-for-Food Programme, is owned by a holding company controlled by Desmarais. [1]

In 1974, Desmarais named employee Paul Martin, Jr. as president of a Power Corporation subsidiary, Canada Steamship Lines Inc.. In 1981, he sold the company to Laurence Pathy and Paul Martin, Jr., the latter of whom became Prime Minister of Canada on December 12, 2003. In 1978 he was made an Officer of the Order of Canada and was promoted to Companion in 1986. Desmarais is a staunch opponent of the Quebec sovereignty movement.

Paul Desmarais sits on the Advisory Board of the giant American corporation, the Carlyle Group.

Desmarais has two sons: Paul Jr. and André Desmarais (who is married to former Canadian Prime Minister Jean Chrétien's daughter France).