Good remark, Jens
Tim said East Africa, so an Indian influence is also possible.
I looked at some of my knives and I found other 'jambiya-type' pieces. All from Africa, but from different regions.
The top one is the one we are discussing.
The second from the top is probably from the Sudan.
Then the one with red leather sheath comes from Mali.
The bottom one probably originates in North Africa.