This item is known in the catalogues as one of the following numbers:
Michel: 8 I (First plate (“small medallions"): oval 16-17 mm high and 14-15 mm large; thin satiny paper) or 8 II (Second plate ("big medaillons"): oval 17-17 mm high and 14-14 mm large; halfthick, thick and granular paper);
Yvert & Tellier: 11 or 11a (round medallion);
Stanley Gibbons: 10 (thin paper) or 14 (thin or thick paper) or 14a (quadrille paper);
OBP: 11A or 11Aa (round medallion, machine-made paper) or 11 or 11a (oblong medallion on machine-made thin to normal paper) or 11B (thick paper).