  We experimentally investigate a non-linear Hall effect for three-dimensional
WTe$_2$ and Cd$_3$As$_2$ single crystals, representing Weyl and Dirac
semimetals, respectively. We observe finite second-harmonic Hall voltage, which
depends quadratically on the longitudinal current in zero magnetic field.
Despite this observation well corresponds to the theoretical predictions, only
magnetic field dependence allows to distinguish the non-linear Hall effect from
a thermoelectric response. We demonstrate that second-harmonic Hall voltage
shows odd-type dependence on the direction of the magnetic field, which is a
strong argument in favor of current-magnetization effects. In contrast, one
order of magnitude higher thermopower signal is independent of the magnetic
field direction.
