This is what French Wikipedia says about Joseph Bonnier de la Mosson:
"Joseph Bonnier (1702-1744) was a French aristocrat of the 18th century. Fortune enabled him to make career in the army, becoming a colonel of the Dragons-Dauphin Regiment and Maréchal-des-logis (staff sergeant) of the Royal Household. He left Paris with the death of his father to take on the responsibilities of Treasurer of Languedoc.
Appointed baron of Mosson, he build a famous folly, the Domaine Bonnier de la Mosson, close to Montpellier. A great science and art lover, he became famous for his collection which was housed in his Parisian home. With his death, his fortune was wasted and his house ransacked."
Such a brief description for such a larger-than-life man.
In 1726, Joseph Bonnier's careful and frugal father died, leaving his twenty-four-year-old son with a fortune worth ten billion francs and a governmental position which paid, possibly unofficially, one hundred thousand écu, or five or six hundred thousand livres (an ecu, just before the Revolution, being equivalent to about $25 in 2006). Being young, insanely rich, and a handsome officer, Bonnier had no problems with spending his money. He loved pomp and splendor, and was known to frequent the theatres, both in the audience and backstage, and showed particular interest in beautiful actresses. He was intelligent and talented, and was able to indulge all his desires for beauty and knowledge without being accountable to anyone - at least, for awhile.
When he took the opera singer known as La Petitpas for his mistress, building her a fanciful palace in the garden of the Hotel de Lude (his luxurious house in Paris), he was
In the National Gallery of Art in Washington, D.C. is a painting by Jean-Marc Nattier of Bonnier, showing a man happy in his obsession:
"Bonnier was the perfect eighteenth-century amateur, whose wealth allowed him the leisure to study nature's curiosities. His large collection, open to the public, held cabinets devoted to anatomy, chemistry, pharmacy, and mechanical engineering. Nattier's portrait shows a man of lively intelligence, informally dressed and in a relaxed pose, surrounded by the objects that held his interest: books about natural history (perhaps a publication he sponsored), jars of biological specimens, and mechanical models." (link)