[en] The present article is concerned by the main theoretical stages of the Error Correction Model (ECM) and its application. The first part starts with the analysis of the stationarity of the series followed by the cointegration test of Johansen and then the estimation of the ECM. The second part gives details of the application of this methodological approach on real data. This study has established that the current price of beans on the market is dependent on the price of white maize flour observed for two days in the first and the second quarter.