The Rieffel deformation is a method of deforming \(\text C^*\)-algebras. This tool can be also used for deforming locally compact groups. Let \(G\) be a locally compact group, \({\Gamma\subset G}\) an abelian subgroup and \(\Psi \) a continuous 2-cocycle on the dual group \({\Hat\Gamma}\). Let \(B\) be a \(\text C^*\)-algebra and \({\Delta_B\in{\text{Mor}}\,(B,B\otimes{\text C}_0(G))}\) a continuous right coaction. In this paper, the author uses the Rieffel deformation to construct a quantum group \({({\text C}_0(G)^{\tilde\Psi\otimes\Psi},\Delta^\Psi)}\) and the deformed \(\text C^*\)-algebra \(B^{\Psi}\). The author presents a construction of the continuous coaction \({\Delta_B^\Psi}\) of the quantum group \({({\text C}_0(G)^{\tilde\Psi\otimes\Psi},\Delta^\Psi)}\) on \(B^{\Psi}\), and he applies it to the action of the Lorentz group on the Minkowski space obtaining a \(\text C^*\)-algebraic quantum Minkowski space.