Article dans une revue: Since 2009, central banks have implemented expansionary policies to support activity and prevent industrialized economies from falling into deflation. In a recessionary environment, policy rates reached an effective lower bound (ELB) which has led central banks to resort to unconventional measures. These policies have resulted in an expansion of their balance sheets, reflecting liquidities provided by central banks to the financial system and asset purchases. These actions have raised many questions about their impact on real activity because recovery has been weak in the Eurozone, notably compared to the United States and the United Kingdom (see chapter 1). In the following, we focus on ECB policies’ impact on investment (section a) and on the impact of credit conditions on investment (section b). Questions have also been raised concerning the possible responsibility of monetary policy in generating financial bubbles (section c). The end of QE finally raises the issue of next engine of growth for the euro area (section d).