We show how the combination of Bias Exchange metadynamics (BE) with Car-Parrinello molecular dynamics (CPMD) can lead to vast improvements in the study of chemical reactions. Bias Exchange metadynamics is a recently introduced methodology that combines replica exchange techniques with the metadynamics approach. It allows fast parallel reconstruction of the free energy of a system in a virtually unlimited number of variables. The value of the method was previously demonstrated for the folding of a Triptophane cage miniprotein on the classical potential energy surface. As a test case for the DFT implementation, we investigated the competitive SN2 reaction of CH3Cl with Cl− and Br−. The results illustrate three important advantages of the method. (1) Fast and complete sampling of configuration space occurs in each replica. (2) A significant speed-up can be observed in the convergence of the free energy profiles, compared with regular metadynamics. (3) The best conformational distributions are successfully transferred from one replica to the others.