Particle-flow commissioning with muons and electrons from J/Psi and W events at 7 TeV

Leptons from $\JPsi$ and W decays collected at 7~\TeV by the CMS experiment in 2010 at the Large Hadron Collider are used to show that the particle-flow lepton identification and reconstruction perform as expected. The particle-based missing transverse energy, computed from all particles in the event, is commissioned in channels featuring leptons.