I picked this one up recently
In its brief two year existence, Rwanda-Burundi issued only this one coin, and quite an attractive one at that. Struck at the Brussels mint.. Low mintage 3,000,000
1964
Obverse
Lion (panthera leo-felidae)
Lettering:
B.E.R.B.
1964
(B.E.R.B. is Rwanda and Burundi Bank of Emission)
Reverse
RWANDA
. 1F .
BURUNDI
File copy - mine is not so clean

The franc became the currency of Rwanda and Burundi in 1916, when the two countries were occupied by Belgium and the Belgian Congo franc replaced the German East African rupie. Rwanda-burundi was created in June, 1960 from the the territories of Rwanda and Burundi in Africa which were controlled by Belgium under a United Nations Mandate. In 1960, the Belgian Congo franc was replaced by the Rwanda and Burundi franc, issued by the Rwanda and Burundi Bank of Emission (B.E.R.B). On July 1, 1962 Rwanda and Burundi were each granted independence, bringing an end to the short-lived existence of Rawanda-burundi. This Rwanda and Burundi franc circulated until 1964, when Rwanda and Burundi introduced their own currencies, the Burundian franc and the Rwandan franc.