Résumé : Measurements of the differential cross sections for the production of exactly four jets in proton-proton collisions are presented as a function of the transverse momentum pT and pseudorapidity Eta, together with the correlations in azimuthal angle and the pT balance among the jets. The data sample was collected in 2010 at a center-of-mass energy of 7 TeV with the CMS detector at the LHC, with an integrated luminosity of 36pb-1. The cross section for exactly four jets, with two hard jets of pT>50GeV each, together with two jets of pT>20GeV each, within