I have two similar variations. Probably both are WW2 manufacture but I believe some ersatz German Imperial produced patterns were made during WW1.
See post #9 on link below:
Frogs, as an accessory to the bayonet and integral piece of German army field gear, are quite collectable. Around the time I posted the article, several others were drafted and submitted as well. So, if you search back through the previous posts to that time period (late 2016), there is additional information available...