It's interesting - a huge untapped source of potential acquisitions for a company like FTE...but the infrastructure is still developing. The last continent for build out and the French still have quite an influence in Africa (not southern Africa of course).
Maybe this will be one area worth watching with the recent FTE acquisition of Mobonil (Egypt).
I live and work in French-speaking West Africa. Factors here which tend to favor FTE are a young and rapidly growing population which will need to communicate (teenagers = phone use, plus Africans tend to be big on staying in contact with their large circle of family and friends). Also as a result of the resource rush, African economies are growing and people are becoming more educated. FTE (Orange) also has an extensive network and good name recognition, and many outlets.
Factors which may not favor FTE in Africa: cheaper competition is always a possibility, plus potential political instability, though this does not typically result in shutting down the phone company. Also people some people who can afford better technology use Magic Jack and Skype for international calls.