This paper adopts the methodology of error correction models on the BEER (Behavioral Equilibrium Exchange Rate) approach to express the Tunisian real effective exchange rate based on-trade openness, the money supply in terms of GDP, and GDP per capita on the period (1975–2017). Indeed, the error correction mechanism confirms one of the convergences of the REER series of its trajectory to its long-term target value and on the other hand, it reflects the success of the monetary and commercial policies exploited to absorb all unpredictable shocks capable of preventing the stability of ERER from its equilibrium value. The empirical results also show the low sensitivity of the REER to monetary and trade shocks.