  The latest searches for flavor changing neutral currents (FCNCs) and
measurements of properties in top quark events at the CMS and ATLAS experiments
are presented. The vast amounts of proton-proton collision data recorded during
the CERN LHC Run 2 at $\sqrt{s} = 13$ TeV provide excellent opportunities to
test the standard model (SM) with increasingly high precision and search for
subtle deviations from the SM expectation. Tight constraints on top quark FCNC
decay branching fractions are derived, and asymmetries of observables sensitive
to new physics are measured.
