International audienceThe magnetic field vectors derived from the Hanle effect measured in prominences during the ascending phase and maximum of Cycle XXI have been plotted on the corresponding synoptic maps of the Meudon Observatory. Most of these measurements have been performed in a single line, He I D3. Our previous analysis of 2 lines measurements have already proved that the prominences magnetic field has the Inverse polarity and remains close to the horizontal plane (Bommier et al., 1994, Solar Physics 154, 231; Bommier et al., 1986, A&A 156, 79). We had also found early that the field component along the filament axis shows a remarkable large scale pattern, especially at high latitudes (Leroy et al., 1983, Solar Physics 83, 135). ...