In this contribution we present gravity field monthly solutions from GRACE Follow-On (GRACE-FO) Level-1B sensor data. The monthly solutions are computed with the GRACE-SIGMA software developed at the Institute of Geodesy, Leibniz University Hannover. The solutions are obtained using a two-step approach. In a first step, the orbits of the two satellites are pre-adjusted by estimating local arc parameters. In a second step, the monthly gravity field potential in terms of normalized spherical harmonic coefficients is recovered. Several parametrization scenarios are tested and the obtained solutions are compared with solutions of other processing centers. Furthermore, K-band range-rate (KBRR) post-fit residuals are analyzed in time, frequency and space domain and are compared to the typical post-fit residuals of the GRACE mission.