Nice job of sleuthing! I was thinking French because "Garantie" is French for
the English word "Guarantee" and I have seen it before on French plane irons.
Turns out that the German word for "Guarantee" is also "Garantie"!
north of Seattle USA
On Sunday, January 16, 2022, 10:45:19 PM PST, Carlo wrote:
it’s German: https://www.holzwerken.de/museum/hersteller/becker_cf.phtml
The plane itself also has a very distinct German shape.