Fermion pair cross-sections and asymmetries and limits on new physics

The measurements of hadron and lepton pair production cross-sections and lepton pair forward-backward asymmetries performed by the ALEPH, DELPHI, L3 and OPAL collaborations are summarized. The results obtained with data taken at centre-of-mass energies between 130 and 207 GeV, including the events recorded in the early summer 2000 at 205 and 207 GeV, show no significant deviations from the standard model predictions. This allows to constrain new physics phenomena like contact interactions, additional heavy gauge bosons Z', models of gravity in extra dimensions, exchange of sneutrinos or squarks in R- parity violating models and leptoquarks.