On the spontaneous break down of massive gravities in 2+1 dimensions
  We show that locally Lorentz invariant, third order, topological massive gravity can not be broken down neither to the local diffeomorphism subgroup nor to the rigid Poincar\'e group. On the other hand, the recently formulated, locally diffeomorphism invariant, second order massive triadic (translational) Chern-Simons gravity breaks down on rigid Minkowski space to a double massive spin-two system. This flat double massive action is the uniform spin-two generalization of the Maxwell-Chern-Simons-Proca system which one is left with after U(1) abelian gauge invariance breaks down in the presence of a sextic Higgs potential. 
C. Aragone, P.J. Arias and A. Khoudeir