In the last five years, we have carried out a comprehensive study of the family of REMn2O5 multiferroics by neutron and X-ray magnetic scattering, providing details about the microscopic origin of ferroelectricity in this family of compounds. We have established that ferroelectricity emerges as a result of symmetric magnetic exchange interaction, unlike for other class of multiferroic. In a recent magnetic X-ray experiment on GdMn2O5, until then an unstudied member of the series, we have found that the magnetic ferroelectric phase is commensurate with a wave-vector k=(1/2,0,0) from 26K down to the lowest temperature. This is unique as other members display a magnetic ordering with k inside the BZ. Crucially, the electrical polarization is 50% higher than for the analogues. The goal of the experiment is to probe the magnetic states above 26K, that we failed to identify with X-ray.