Jean Lemoine, Jean Le Moine, Johannes Monachus (born 1250 at Crécy-en-Ponthieu, died 22 August 1313 at Avignon) was a French canon lawyer, Cardinal, bishop of Arras and papal legate. He served Boniface VIII as representative to Philip IV of France, and founded the Collège du Cardinal Le Moine, in Paris.
He was awarded degrees in canon law and theology by the University of Paris. He then became a canon of the cathedral chapters at Amiens and then in Paris. A royal adviser, he travelled to Rome, and was made Auditor of the Rota in 1282.
Master Jean Le Moine was Dean of Bayeux Cathedral, from 1288 to 1292. He was actually, during that period, not in Bayeux, but at the Papal Curia, serving as Vice-Chancellor. He signed the papal bulls under Pope Nicholas IV (1288-1292) as Magister Johannes Decanus Baiocensis.
Jean Le Moine was then elected bishop of Arras after the death of Bishop Guillaume de Issiaco on September 23, 1293. The election was finally confirmed by Boniface VIII.
Pope Celestine V created him cardinal, with the title of Saints Marcellino e Pietro, at the consistory of 18 September 1294. On 21 June 1295, he was in Anagni and attended the Consistory in which Pope Boniface recognized King James II of Aragon as the successor of King Pedro; Johannes tit. S. Marcellini et Petri presb. Card. subscribed to the bull. He is attested among the cardinal-priests, under the name Johannes Monachus, as being present in the Roman Curia and receiving his share (1/18 on this occasion) in a distribution of the income from the Treasury of the College of Cardinals on 25 November 1295. He appears again on 10 May 1297, as one of nineteen cardinals who received a share of the 50% of the income of the two deposed Colonna cardinals, thanks to the generosity of Pope Boniface VIII. When the procurator of the Bishop of Siena paid in 300 livres Tournois around 24 June 1297, Jo. Monachus was one of seventeen cardinals entitled to a share. There were many other distributions in which the names of the recipient cardinals are not listed, but which undoubtedly brought Cardinal Le Moine various sums of money. At Easter, 1297, the Archbishop of Tours paid in 200 livres Tournois, 1/15th of which went to Cardinal Le Moine, and around Pentecost, he received 1/16 of the 500 livres Tournois presented by the Archbishop of Rouen. On 5, September, thanks to the payment of the Abbot Majoris Monasterii (Marmoutier) in Tours of 180 livres Tournois, the Cardinal received a 1/15th share. In the winter of 1297/1298 he was appointed Auditor by Pope Boniface in the case of a Dominican Inquisitor and a Milanese soldier. In the winter of 1297/1298 he was appointed Auditor along with Cardinal Nicolas de Nonancourt by Pope Boniface in a case involving the Diocese of Lund and the King of Denmark.