I am interested in knowing when, where, and by whom "country of origin" labels (e.g. "Made in France") were first used on consumer goods.
Country-of-origin marking laws were first enacted in the 1880s in various European countries* to distinguish imported goods (particularly German goods) from domestic goods, and became mandatory in the United States in 1891 with the enactment of the Tariff Act of 1890 (p. 1-3).
These laws have since been worked and reworked countless times, but "the United States is considered to maintain the broadest and most stringent set of marking requirements" (p. 1-3). The Tariff Act of 1930 seems to have been particularly influential in American Country of Origin Labeling law.
Of course, voluntary labeling of country of origin may have predated these laws from the 1880s. Consumption of foreign goods has often become politically fraught, as evidenced by the non-consumption movement in pre-revolution America and the later Non-Importation Act.
* Unfortunately, the report cites a 1924 Tariff Commission report that isn't accessible online, so I'm not sure exactly which countries these were. The UK may have been one of the first, with the passage of the Merchandise Marks Act of 1887.
Country of origin requirements were not common law until 1891. (MADRID AGREEMENT CONCERNING THE INTERNATIONAL REGISTRATION OF MARKS)
In 1890, the U.S. Congress passed protectionist tariff legislation - the McKinley Tariff. This legislation, in addition to imposing heavy tariffs on imports and provoking a major depression in the United States, also required that imported items be labeled with their country of origin.
Every article of foreign origin entering the United States must be legibly marked with the English name of the country of origin unless an exception from marking is provided for in the law.
Originally articles imported to the US were marked with the Country only i.e. "Bavaria." If you see a mark that simply says a country name it was likely made after 1890 for export to the United States.
In 1914, the U.S. added the requirement of the words "Made in" to the Country of origin marking. Thus new imports after that date were marked i.e. "Made in Czechoslovakia"