We discuss a small-scale experiment, called ν -cleus, for the first detection of coherent neutrino–nucleus scattering by probing nuclear-recoil energies down to the 10 eV regime. The detector consists of low-threshold CaWO 4 and Al 2 O 3 calorimeter arrays with a total mass of about 10 g and several cryogenic veto detectors operated at millikelvin temperatures. Realizing a fiducial volume and a multi-element target, the detector enables active discrimination of γ , neutron and surface backgrounds. A first prototype Al 2 O 3 device, operated above ground in a setup without shielding, has achieved an energy threshold of ∼ 20  eV and further improvements are in reach. A sensitivity study for the detection of coherent neutrino scattering at nuclear power plants shows a unique discovery potential (5 σ ) within a measuring time of ≲ 2  weeks. Furthermore, a site at a thermal research reactor and the use of a radioactive neutrino source are investigated. With this technology, real-time monitoring of nuclear power plants is feasible.