AbstractIn the functional integral formalism of quantum field theory a gauge breaking term is added to the classical action in order to parametrize the orbits of the gauge group. In quantum gravity this gauge breaking term fixes the orientation of the Riemannian metric with respect to a fixed reference metric. We explain the notion of gauge invariance this procedure is based on. A special gauge fixing term is considered, which together with the Einstein‐Hilbert action leads to Rosen's bimetric theory with arbitrary background. Discussing some consequences of this gauging for quantum gravity, it is especially shown that there are some difficulties if back reaction is regarde