  We prove that, if a group is relatively hyperbolic, the parabolic subgroups
are virtually nilpotent if and only if there exists a hyperbolic space with
bounded geometry on which it acts geometrically finitely.
  This provides, by use of M. Bonk and O. Schramm embedding theorem, a very
short proof of the finiteness of asymptotic dimension of relatively hyperbolic
groups with virtually nilpotent parabolic subgroups (which is known to imply
Novikov conjectures
