  It is shown that the topological action for gravity in 2n-dimensions can be
obtained from the 2n+1-dimensional Chern-Simons gravity genuinely invariant
under the Poincare group. The 2n-dimensional topological gravity is described
by the dynamics of the boundary of a 2n+1-dimensional Chern-Simons gravity
theory with suitable boundary conditions. The field $\phi^{a}$, which is
necessary to construct this type of topological gravity in even dimensions, is
identified with the coset field associated with the non-linear realizations of
the Poincare group ISO(d-1,1).
