In Quebec, on March 24, 1937, the Union Nationale government of Maurice Duplessis passed the Padlock Law, which permitted closing any premises suspected of producing or distributing communist propaganda.

The law was ill-defined and denied the presumption of innocence, and was often abused by the Duplessis government against political opponents and groups it considered undesirable, such as the Jehovah's Witnesses. In 1957, the Supreme Court of Canada struck down the law as unconstitutional.