Monitoring the muon beam properties in the final stage of the Neutrino Factory (the Decay Ring) is important for the understanding of the beam itself and a crucial piece of information for the downstream physics. The main topics to be assessed are: knowledge of the muon beam energy and polarization, divergence of the beam and beam current. In the framework of the International Design Study for the Neutrino Factory (IDS-NF) a racetrack model Decay Ring based on G4Beamline has been produced to simulate electrons from muon decays and the measurement of the beam energy distribution via the spin precession technique. The use of other codes, like Zgoubi, to generate a realistic beam including effects like spin polarization, are considered. A general discussion on future work is presented.