The organic-inorganic perovskites (CH3NH3Pb(Br,Cl,I)3) have been identified as efficient photovoltaic materials. Recent neutron scattering results on powder has shown a strong coupling between the organic molecules and the inorganic framework. Here we propose a single crystal neutron diffraction study on CH3NH3PbCl3 to measure the diffuse scattering related to the organic molecular dynamics in this compound. Polarized neutrons on D7 are necessary to separate the incoherent signal coming from the hydrogen atoms from the coherent diffuse scattering we would like to study. We would also like to check any additional contribution on Bragg peaks as the organic molecules lock at low temperature and record data to refine the thermal factors related to the hydrogen displacements on D10.