|Cape Verde*||Kenya||Mauritania*||South Africa||Zambia|
Of these, I've italicized those countries in which French is a national language, and I've marked with an asterisk those countries which are member states of la Francophonie (formerly Organisation Internationale de la Francophonie, or OIF). [NOTE: I've ignored Ghana, an Associate Member, and Mozambique, an Observer.]
Since I don't know exactly what definition the Peace Corps uses for Francophone sub-Saharan Africa, I'll go with the slightly longer list of members of la Francophonie, which includes all of the countries in which French is a national language (Benin, Burkina Faso, Cameroon, Guinea, Madagascar, Mali, Niger, Senegal, and Togo) and two countries in which French is NOT a national language (Cape Verde and Mauritania). This is in part because I would like it to be true, because I think I would particularly enjoy Cape Verde. Plus, I already know someone there.