The interest in the noncollinear antiferromagnet Mn3Ge was stirred by the recent observation ofan anomalous Hall effect (AHE) driven by nonvanishing Berry curvature, which typically vanishesfor conventional (collinear) antiferromagnets. Our most recent anomalous- Hall- effect andmagnetization measurements suggest a very strong sensitivity of the magnetic transitions andpresumably of the magnetic structure and AHE to hydrostatic pressure. Even very modestpressures of the order of a few kbar led to a notable reduction of the antiferromagnetic transition temperature and to the stabilization of a new low-temperature magnetic phase. We propose to study the magnetic structure of this pressure-induced phase transition by neutron single crystal diffraction at the Wish instrument at ISIS.