It is now a common practice to establish stationarity of the real exchange rate as a sign of
purchasing power parity (PPP) hypothesis. In this article, we consider the real effective exchange
rates of 29 African countries. When we apply conventional linear unit root tests, we find support
for the PPP in eight countries. However, when we shift to the newly introduced non-linear
quantile unit root test, support for the PPP increases to 15 countries