Dear Yvain, Thank you for your response. I was led to the idea of Hausa by the shape of the guard on the wooden handle, which is similar to some Hausa daggers .
http://www.vikingsword.com/vb/showth...t=Hausa+dagger
The triangular engravings on the blade seem to me to be typical for the blades of the southern part of the Sahel (there are also also similar engravings on some spearheads in northern Cameroon).
I have had three swords consecutively from the Yaka ethnic group and I believe it is not the same case.
Best,
Martin