This art form is called "Papal Amate" or Paintings on Amate bark paper. This was made in Mexico, and they are produced through a trade alliance among two Native tribes the Otomi who make the paper an Nahua who decorate it. Yours would date to the mid 20th century at the earliest. They are sold to the tourist and decorator trade. On today's market, this could sell for $15 - $30 at auction. The suggested insurance or replacement value is $50.
Here is a link for you about Amate paper and how the art evolved:
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