Africa is growing rapidly and presents opportunities for profitable investments, if risky ones. The opportunities vary by industrial sector. Here are DRC industries ranked by the average growth of the companies in them over the period 2009-2012. Non-metallic mineral products was the fastest growing industry, and fabricated metallic mineral products was the slowest growing.
I am not entirely confident that the reported returns accurately reflect economic performance (since there is some disagreement with macroeconomic growth figures), so the ranks are given rather than the actual values.