  Particles propagating in de Sitter spacetime can be described by the
topological BF $\SO(4,1)$ theory coupled to point charges. Gravitational
interaction between them can be introduced by adding to the action a symmetry
breaking term, which reduces the local gauge symmetry down to $\SO(3,1)$, and
which can be treated as a perturbation. In this paper we focus solely on
topological interactions which corresponds to zeroth order in this perturbative
expansion. We show that in this approximation the system is effectively
described by the $\SO(4,1)$ Chern-Simons theory coupled to particles and living
on the 3 dimensional boundary of space-time. Then, using Alekseev--Malkin
construction we find the effective theory of particles kinematics. We show that
the particles action contains standard kinetic terms and the deformation shows
up in the presence of interaction terms. The strength of the interactions is
proportional to deformation parameter, identified with Planck mass scale.
