"Not to be confounded with his uncle John II of Saarbrücken-Commercy " 
John II of Saarbrücken, Jean II de Sarrebruck, Johann II von Saarbrücken (circa 1310 – 11 March 1381). He was the Count of Saarbrücken and Seigneur (lord) of Commercy , as Jean IV of Saarbrücken-Commercy, part "Château bas".
Life.
John was the son of Simon of Saarbrücken-Commercy (d. 1325), son of John I (b. 1265 - 1341/42), Count of Saarbrücken. His mother was Marguerite of Savoy-Vaud (d. 1313), a daughter of Louis I of Vaud, married with Simon in 1309.
1326, before the death of John II's grandfather, Count John I, the inheritance was divided. John was awarded the County of Saarbrücken and a small part of Commercy, called "Saarbrücken" or "Château bas". The larger part of Commercy, called "Château haut", went to his "uncle" John II (Jean II) , as "Seigneur of Commercy", of the house of Saarbrücken-Commercy. One of his sons was Jean III.
Like his father Simon, John II supported France in the war against England. During the Battle of Poitiers 1356, both John II and King John II of France were taken prisoner by the English. He was held in Wallingford Castle until 1360.
In 1362, he fought against gangs of mercenaries near Lyon and was briefly taken prisoner again. John II undertook several diplomatic missions in the service of the French King. In 1362, he travelled to the court of Emperor Charles IV and in the following years, he travelled to the English court several times. In 1364, he was appointed Grand Butler of France as a reward for his services. In 1370 John was appointed chairman of the Court of Finances. In 1371, he received the Lordship of Vaucouleurs.
In 1380, John II retired from the French court. He died in 1381. As he had no sons, his daughter Johanna inherited the County of Saarbrücken. However, she died later that year, and the county fell to her son Philipp I of Nassau-Weilburg. Various lines of the House of Nassau would hold the county until it was conquered by France in 1795.
Marriage and issue.
Latest in 1334, John II married Ghislette (d. 1356/62), a daughter of Peter of Bar (d.c. 1348), Lord of Pierrefort, son of Theobald II, Count of Bar. Ghiselette's mother was Jeanne of Vienne (d.b. 1326), daughter of Hugues of Vienne (d. 1307?), Sire of Longwy and Pagny (or Philipp I, Count of Vianden?). John and Ghislette had one daughter: