  In this work we present a BMS-like ansatz for a Chern-Simons theory based on
the semi-simple enlargement of the Poincar\'e symmetry, also known as
AdS-Lorentz algebra. We start by showing that this ansatz is general enough to
contain all the relevant stationary solutions of this theory and provides with
suitable boundary conditions for the corresponding gauge connection. We find an
explicit realization of the asymptotic symmetry at null infinity, which defines
a semi-simple enlargement of the $\mathfrak{bms}_3$ algebra and turns out to be
isomorphic to three copies of the Virasoro algebra. The flat limit of the
theory is discussed at the level of the action, field equations, solutions and
asymptotic symmetry.
