In comparison with Scandinavian countries, Belgium taxes energy relatively less than labour. But what would happen if we implemented a tax shift aimed at increasing taxes on energy and decreasing employers’ or employees’ labour taxes proportionally? In this report, the Federal Planning Bureau makes some simulations to answer the question. Even if the effect on the GDP is expected to be neutral, such a measure generates what economists call a double dividend: employment increases on the one hand and energy consumption and CO2 emissions decrease on the other hand.