History / Need Help - mysterious object identification. Could it be Polish? [19]

Hi,

I recently dug up this object in my belgian garden. It's an iron/tin cup with a length of 4 cm. It has a white eagle against a red background. On the belly of the eagle there are two letters: CF.

Could this be Polish? (They liberated Belgium in the second world war) And what would the CF stand for?

thanks in advance.

Here you can see the pic:

warrelics.eu/forum/polish-armed-forces-second-republic-si-y-zbroj ne-ii-rzeczypospolitej-polskiej-1918-1939/mysterious-tin-cup-hera ldic-eagle -210975/