Internal and external imbalances in the global economy have risen debates on exchange rates and their links with competitiveness, balance of payments and sustained growth. Some of these debates refer to how current and capital accounts distortions are produced jointly with misalignments in real exchange rates (RER). There are mainly two macroeconomic models to explain RER behaviour: the purchasing power parity (PPP) and the Balassa – Samuelson effect. To infer the theory that best fits empirical data, this research will contrast the PPP theory and find a relationship between RER, its real determinants and tariffs. I focus on two empirical cases: the Euro Zone and the BRICS countries. Cointegration techniques underlie the long run relationship when the method of ordinary least squares (OLS) with error correction mechanism (ECM) shows the short term relationship. On one hand, explaining the above mentioned relations, the RER’s overvaluations or undervaluations can be calculated in the Euro Zone. On the other hand, I show tariffs decreases effects on the exchange rate misalignment in the BRICS countries to correct them through economic policies.