  Deformed relativistic kinematics, expected to emerge in a flat-spacetime
limit of quantum gravity, predicts violation of discrete symmetries at energy
scale in the vicinity of the Planck mass. Momentum-dependent deformations of
the C, P and T invariance are derived from the \k{appa}-deformed Poincar\'e
algebra. Deformation of the CPT symmetry leads to a subtle violation of Lorentz
symmetry. This entails some small but measurable phenomenological consequences,
as corrections to characteristics of time evolution: particle lifetimes or
frequency of flavour oscillations in two-particle states at high energy. We
argue here that using current experimental precisions on the muon lifetime one
can bound the deformation parameter \k{appa} > 10^14 GeV at LHC energy and move
this limit even to 10^16 GeV at Future Circular Collider, planned at CERN.
Weaker limits on deformation can be also obtained from interference of neutral
mesons. In case of B0s from {\Upsilon} decay it amounts to \k{appa} > 10^8 GeV
at confidence level 99%.
