This is a Dutch Army Military Cap / Kepie model 1916 M16 (laag model) with metallic cockarde, indicating it was for “manschappen”.
For Infanterie Regiment 6 as indicated by the number on the front.
There’s a “Je Maintiendrai” dutch makers stamp on the inside.
In very condition for it’s age. A few very minor age spots on the edge, but actually pretty good for it’s age.
These early low model caps are hard to find!