I'm not sure that there is a specific law relating to breastfeeding that came into play in this incident in Winnipeg. Rather, the right to breastfeed in Canada derives from court interpretations of provincial Human Rights Codes and probably also
Section Fifteen of the Canadian Charter of Rights and Freedoms, which prohibits discrimination on the basis of sex.
I couldn't find specific guidance from the Manitoba Human Rights Commission, but the part of the article I put in bold type explains that commission's position.
A document from the Ontario Human Rights Commission,
POLICY ON DISCRIMINATION BECAUSE OF PREGNANCY AND BREASTFEEDING, states:
The Supreme Court of Canada has stated that pregnancy cannot be separated from gender. Pregnancy discrimination is a form of sex discrimination simply because of the basic biological fact that only women have the capacity to become pregnant.6 Section 10(2) of the Code states that “The right to equal treatment without discrimination because of sex includes the right to equal treatment without discrimination because a woman is or may become pregnant.”
“Pregnancy” includes the process of pregnancy from conception up to the period following childbirth and includes the post-delivery period and breastfeeding.
I think the Human Rights Commission in every Canadian province and territory would interpret the Supreme Court's ruling in the same manner.
Breastfeeding in public is permitted by law in most states in the U.S.A.
State Breastfeeding Laws in the United States: Forty-four states, the District of Columbia and the Virgin Islands have laws with language
specifically allowing women to breastfeed in any public or private location (Alabama, Alaska, Arizona, Arkansas, California, Colorado, Connecticut, Delaware, Florida, Georgia, Hawaii, Illinois, Indiana, Iowa, Kansas, Kentucky, Louisiana, Maine, Maryland, Massachusetts, Minnesota, Mississippi, Missouri, Montana, Nevada, New Hampshire, New Jersey, New Mexico, New York, North Carolina, North Dakota, Ohio, Oklahoma, Oregon, Pennsylvania, Rhode Island, South Carolina, Tennessee, Texas, Utah, Vermont, Washington, Wisconsin and Wyoming).
Twenty-eight states, the District of Columbia and the Virgin Islands exempt breastfeeding from public indecency laws (Alaska, Arizona, Arkansas, Florida, Illinois, Kentucky, Louisiana, Massachusetts, Michigan, Minnesota, Mississippi, Montana, Nevada, New Hampshire, New York, North Carolina, North Dakota, Oklahoma, Pennsylvania, Rhode Island, South Carolina, South Dakota, Tennessee, Utah, Virginia, Washington, Wisconsin and Wyoming).
Twenty-four states, the District of Columbia and Puerto Rico have laws related to breastfeeding in the workplace (Arkansas, California, Colorado, Connecticut, Georgia, Hawaii, Illinois, Indiana, Maine, Minnesota, Mississippi, Montana, New Mexico, New York, North Dakota, Oklahoma, Oregon, Rhode Island, Tennessee, Texas, Vermont, Virginia, Washington and Wyoming).
Twelve states and Puerto Rico exempt breastfeeding mothers from jury duty (California, Idaho, Illinois, Iowa, Kansas, Kentucky, Mississippi, Montana, Nebraska, Oklahoma, Oregon and Virginia).
Five states and Puerto Rico have implemented or encouraged the development of a breastfeeding awareness education campaign (California, Illinois, Minnesota, Missouri and Vermont).
source: National Conference of State Legislatures
http://www.ncsl.org/default.aspx?tabid=14389