$\kappa$–de Sitter and $\kappa$-Poincaré symmetries emerging from Chern-Simons $(2+1)\mathrm{D}$ gravity with a cosmological constant

Defining a new $r$-matrix compatible with the scalar product at the basis of the Chern-Simons action for a particle coupled to ($2+1$) Lorentzian gravity with cosmological constant, I show how deformed symmetries of $\kappa$-de Sitter and, in the vanishing cosmological limit, of $\kappa$-Poincaré kind, arise naturally as quantum deformation of three dimensional gravity. I obtain, moreover, the noncommutative spacetime associated with these kinds of symmetries.