Louise Marie Madeleine Fontaine
Jean-Jacques Rousseau subsequently sent an inflamed letter to Madame Dupin, who returns him expressing her concern. This doesn't stop the writer for much and only the intervention of Louise's stepson put an end to his attentions. But Madame Dupin was hardly spiteful and some months after these incidents, takes Rousseau in her service and put him in charge of the education of her son Jacques-Armand for eight days pending for a new tutor. Subsequently, the Dupins taken Jean-Jacques Rousseau as secretary after their return from Venice in 1745, when he is not yet a writer and for a modest salary. His job was to take notes and research for the book projected by Madame Dupin, namely "the defense of women in the 18th century are discussed in minor ... until they died". Madame Dupin stood Rousseau almost to a subordinate or, in the words of Grimm and Marmontel, she gives him leave the day it receives academicians. Jean-Jacques Rousseau feels bitterness after leaving his job as a secretary in 1751, but will always keep good relations with the Dupin family. Madame Dupin provides financial support to his wife, Marie-Thérèse Levasseur, who gave birth to five children abandoned by Rousseau to the Foundling Hospital. As for Louis Claude Dupin, his bound with Rousseau came for their common passion for music. The stepson of Madame Dupin was interested in physics, chemistry and natural history, hoping to integrate the Academy of Sciences and the philosopher did write an unfinished book, popular science to "Institutions of Chemistry".
Prince Xavier of Bourbon-Parma
Residing in Paris and sustained by his remaining portion of the family wealth, Xavier reached his mid-30s before making marriage plans; his fiancée being Madeleine de Bourbon-Busset, who was nine years his junior and the daughter of the Count de Lignières. She belonged to a non-royal branch of the French Bourbons. The Bourbon-Bussets have been the subject of a centuries-old controversy: historically regarded as non-dynastic when the line was founded, it has never been established that the Bourbon ancestor from whom they undisputedly descend, Louis de Bourbon, Bishop of Liège (1436-1482), was ever lawfully married. The proposed marriage of Prince Xavier and Madeleine might deprive their children of Bourbon-Parma ducal succession rights, depending upon the decision of the head of the house. Since the death of Duke Robert, Prince Élie, Xavier's eldest half-brother, headed the family. He declared the would-be marriage morganatic. Despite this obstacle, Xavier wed Madeleine in 1927 and some newspapers titled her "princesse".
As the Bourbon-Bussets enjoyed significant wealth, the marriage changed the financial status of Xavier. The couple settled in Bostz castle, where Xavier managed the rural estate of his in-laws. Their eldest, Hugues, was born in 1928 and was followed by five more children, the last one was born in 1940. Following the 1932 death of his father-in-law, Xavier became head of the family's enterprise, including the Château de Lignières. Little is known of his public activity at that time, except that he was engaged in various non-political, Catholic initiatives. In 1934 the premature death of Sixte deprived Xavier of his closest comrade.