  We consider the azimuthal angle dependence in the cross section of the hard
leptoproduction of a photon on a nucleon target. We show that this dependence
allows to define observables that isolate the twist-two and twist-three sectors
in the deeply virtual Compton scattering amplitude. All twist-two and
twist-three Compton form factors can be extracted from measurements of the
charge odd part of the polarized cross section and give access to all
generalized parton distributions.
