I found a picture on German Colonial Uniforms with this discription:

East Africa Schutztruppe Officer
He carries a kS98 bayonet. Although officers and senior NCOs were entitled to carry swords, they often carried privately purchased bayonets in preference, the kS98 being a popular choice. As an officer he carries a sword knot rather than a bayonet knot on the kS98 however.
Photo © Frankfurt University Koloniales Bildarchiv