Brasset became secretary of the French resident (permanent representative) in Brussels in 1616. In 1627 he became secretary of the French Embassy in The Hague and, in 1634, resident. With a short interruption in 1645–46, when he took part in the talks that would lead to the Peace of Westphalia (1648), he remained in The Hague until 1654. He returned to France, “old and blind” it seems and bitter because the States General had not given their usual gratification. He spent his last years in impoverished circumstances, also because his wages had never been paid. It is not known when he died. The first time Brasset is referred to by Descartes is simply as one who could introduce him to the ambassador (AT IV 23–25). Over the years, however, their relations became more familiar; in his last letter to Descartes, Brasset speaks of his little daughter Marie-Charlotte as someone whom Descartes knows and loves (AT V 450). Brasset's intimate knowledge of the official world proved valuable during Descartes’ conflicts with the universities of Utrecht and Leiden (see Heereboord, Adriaan; Regius, Henricus; and Voetius, Gysbertus). In his farewell letter to Brasset, Descartes speaks of his regret about exchanging what must have been for both a second fatherland for “a country of bears” where he must live amid “rocks and ice” (AT V 349–50, CSMK 375–76).

See also Heereboord, Adriaan; Regius, Henricus; Voetius, Gysbertus