My sense is the Smurfs were probably inspired by Brigadoon, a very famous Broadway musical (Lerner & Loewe) that was adapted into a very famous film starring Gene Kelly and Cyd Charisse.

The story involves two American tourists who stumble upon Brigadoon, a mysterious Scottish village that appears for only one day every 100 years.
_{Brigadoon (wiki)}

The name Brigadoon derives from the real Brig o' Doon, a bridge near Alloway, Scotland, and a feature of Robert Burns' folkloric poem Tam o' Shanter.

It's possible the Brigadoon story derives from folktale, but I'm not fining any reliable online sources. However, I found an excerpt attributed (without specific citation) to a book Lost Lands, Forgotten Realms: Sunken Continents, Vanished Cities, and the Kingdoms That History Misplaced which reads: “the spell that was cast over Brigadoon was put in place to protect it from advancing English Redcoats during the Jacobite Rebellion.”

My sense is the Smurfs were probably inspired by Brigadoon, a famous Broadway musical (Lerner & Loewe) that was adapted into a very famous film starring Gene Kelly and Cyd Charisse.

The story involves two American tourists who stumble upon Brigadoon, a mysterious Scottish village that appears for only one day every 100 years.
_{Brigadoon (wiki)}

The name Brigadoon derives from the real Brig o' Doon, a bridge near Alloway, Scotland, and a feature of Robert Burns' folkloric poem Tam o' Shanter.

It's possible the Brigadoon story derives from folktale, but I'm not finding any reliable online sources. I did an excerpt attributed (without specific citation) to a book Lost Lands, Forgotten Realms: Sunken Continents, Vanished Cities, and the Kingdoms That History Misplaced which reads: “the spell that was cast over Brigadoon was put in place to protect it from advancing English Redcoats during the Jacobite Rebellion.”