This article examines the effects of the fluctuation of the prices of exports commodities on the effective exchange rate in WAEMU over the period 1999-2016 in order to appreciate the consumption behaviour of households. In this respect, the Pooled Mean Group (PMG) approach applied to a BEER model was used. The results show that commodity prices are the main factor in the real appreciation of the long-term exchange rate in WAEMU. However, this variable does not help to explain the short-term dynamics. Moreover, we show that the anchor currency is a factor of appreciation in the short term and not in the long term. This justifies the perpetual rumours of devaluation following the sudden overvaluation of the euro. These results suggest preventive measures to contain the adverse effects of possible abrupt fluctuations of the anchor currency on household consumption.