If you sponsor from Quebec, Quebec's own immigration law supplies the undertaking and Quebec decides whether you can afford it. An officer approves the sponsorship only once the province has confirmed you were able to meet the undertaking both on the day you gave it and on the day the decision was made. Several of the federal sponsor rules step aside in exchange.
137 If the sponsor resides in the Province of Quebec, the government of which has entered into an agreement referred to in paragraph 131(b), (a)the sponsor’s undertaking, given in accordance with section 131, is the undertaking required by An Act respecting immigration to Québec, R.S.Q., c.I-0.2, as amended from time to time; (b)an officer shall approve the sponsorship application only if there is evidence that the competent authority of the Province has determined that the sponsor, on the day the undertaking was given as well as on the day a decision was made with respect to the application, was able to fulfil the undertaking; and (c)subsections 132(4) and (5) and paragraphs 133(1)(g) and (i) do not apply.
137.1 (1) The Minister may collect the social insurance numbers of a sponsor and a co-signer who have submitted an application to sponsor a person set out in clause 133(1)(j)(i)(B), in order to verify that they meet the requirements set out in clause 133(1)(j)(i)(B) and in paragraph 133(1)(k). (2) The Minister may disclose the social insurance numbers of the sponsor and the co-signer to the Canada Revenue Agency for the purposes set out in subsection (1) if the Minister has entered into an arrangement with the Agency for the disclosure of that information.