  Weyl semimetals are well known for their anomalous transport effects caused
by a large fictitious magnetic field generated by the non-zero Berry curvature.
We performed the analysis of the electrical transport measurements of the
magnetic Weyl semimetal Mn$_{3}$Ge in the a-b and a-c plane. We have observed
negative longitudinal magneto-resistance (LMR) at a low magnetic field ($B<1.5$
T) along all the axes. The high field LMR shows different behavior along x and
z axes. A similar trend has been observed in the case of planar Hall effect
(PHE) measurements as well. The nature of high field LMR along the x axis
changes near 200 K. Dominant carrier concentration type, and metallic to
semimetallic transition also occur near 200 K. These observations suggest two
main conclusions: (i) The high field LMR in Mn$_3$Ge is driven by the metallic
- semimetallic nature of the compound. (ii) Mn$_3$Ge compound goes through an
electronic band topological transition near 200 K. Single crystal neutron
diffraction does not show any change in the magnetic structure below 300 K.
However, the in-plane lattice parameter (a) shows a maximum near 230 K.
Therefore, it is possible that the change in electronic band structure near 200
K is driven by the a lattice parameter of the compound.
