We present a simplified way to access and manipulate the topology of massive Dirac fermions by means of scalar potential. We show systematically how a distribution of scalar potential can manipulate the signature of the gap or the mass term as well as the dispersion leading to a band inversion via inverse Klein tunnelling. In one dimension it can lead to the formation of edge localisation. In two dimensions this can give rise to an emergent mechanism, which we refer to as the Scalar Hall Effect. This can facilitate a direct manipulation of topological invariants, e.g. the Chern number, as well as allows to manipulate the edge states locally and thus opens new possibilities for tuning physical observables which originate from the nontrivial topology.