Thats absolutely local for me!
A helmet worn during the short insurrection time in the Schleswig-Holsteinische Armee which fought again the Kingdom of Denmark for freedom and independance.
Note the very scarce blue white red cockade that has been only worn between the 7. September 1848 (after the french revolution of February 1848) till the 29. March 1851 ( beginning of the end was the defeat of the battle of Idstedt, 20 km from my home, 25. July 1850). But this cockade had to be worn on the left side! On the right side, there was the black-red-gold cockade here missing (Deutsche Kokarde that symbolized the union with the german Confederation) that was adopted on the 9. March 1848.
Blue-white-red are still the colours of the french flag as the colours of the Schleswig-Holstein flag, and black-red-gold the colours of the german flag.
Philippe