An Etymological Dictionary of the German Language/Pacht
Pacht, f., ‘compact, lease, tenure,’ from MidHG. (MidG.) paht, with the strictly permutated and more usual forms phaht, phahte (MidHG.), f. and m., ‘rent, lease, justice, law’; so too Du. pacht. The ModHG. form is due to LG. influence, as is indicated by the initial sound compared with MidHG. phahte. It is based on MidLat. pactum, pactus, ‘compact, a sum stipulated by the compact.’ OHG. *pfahta is not recorded, probably only by chance, though OHG. (also MidHG.) pfât occurs a few times.