Holbach used his great wealth to throw the dinner parties for which he is famous. He owned a house in Paris in rue Royale, butte Saint-Roche, which, generally, had a guest list restricted to serious intellectuals, and a chateau at Grandval where, in addition to his coterie, Holbach also hosted social friends and relatives. Holbach's coterie included intellectuals who, although their positions varied on many issues, shared at least a willingness to entertain views that many would have thought too radical to be discussed in social settings. The coterie met from the 1750's into the 1780's. The group evolved over time, but its core members, Alan Kors has argued, were Denis Diderot, the encyclopedist; the diplomat and cultural critic Friedrich-Melchior Grimm; the naturalist Charles-Georges Le Roy; the writer and critic Jean-François Marmontel; the historian and priest abbé Guillame-Thomas-François Raynal; the doctor Augustin Roux; the poet and philosopher Jean-François de Saint-Lambert; the writer Jean-Baptiste-Antoine Suard; the pamphleteer François-Jean, chevalier de Chastellux, the pamphleteer abbé André Morellet; and the philosopher Jacques-André Naigeon. Many of these men were, like Holbach, avowed atheists and many also pushed radical, even revolutionary political agendas. So the general character of his coterie might suggest that Holbach was a figure on the fringe of Parisian society, a kind of eccentric parvenu with a taste for scandal.

What is really remarkable about Holbach, however, is that he managed, despite what one might expect, to keep his coterie firmly in the mainstream of European society. French nobles, as well as ambassadors from countries across Europe — Denmark, England, Naples, Saxe-Gotha, Saxe-Coburg-Gotha, Wurtemburg, and Sweden -- attended his dinners. So did prominent intellectuals of all kinds, including, at different times and with different degrees of enthusiasm, the philosopher and novelist Jean-Jacques Rousseau, the mathematician Jean Le Rond d'Alembert, the historian Edward Gibbon, the writer Horace Walpole, the chemist Joseph Priestley, the social critic Cesare Beccaria, the philosopher Nicolas-Antoine Boulanger, the statesman and scientist Benjamin Franklin, the actor David Garrick, the philosopher Claude-Adrien Helvétius, the philosopher David Hume, the economist Adam Smith, and the novelist Lawrence Stern. Holbach was known in France not primarily as a political radical but as le premier maître d'hôtel de la philosophie. Many in Paris coveted invitations to rue Royale, and Holbach's house was the first stop for many prominent international visitors.

Holbach's character must have been remarkable to have maintained a salon in which the espousers of political and religious reform met so freely and so often with visitors who either cannot have been accustomed to such open dialogue or who were themselves parts of the establishment under attack. Indeed Rousseau, who himself came to feel unwelcome by the coterie, nevertheless memorializes Holbach in La nouvelle Heloïse, as the paradoxical figure, Womar, an athiest who nonetheless embodies all of the Christian virtues. In addition to his good character, Holbach's generosity at table (his dinners and especially his wine were famously good) and in supporting many of his acquaintances may explain his success at being both a pillar and a critic of society. Perhaps, also, Holbach was not in the eyes of many of his contemporaries as clearly a radical as some other members of his coterie. He did publish some of the most notorious works of the French Enlightenment, including Le Christianisme Dévoilé (Christianity Unveiled), Système de la nature (System of Nature) and Le Bon-sens (Common Sense). These books evoked long and heated responses from such notable figures as Voltaire, abbé Bergier, and Frederick the Great; System of Nature and Common Sense were condemned by the parlaiment of Paris and publicly burned. Holbach, however, was not in his own time as notorious as his books. He was careful always to publish anonymously, so that those who did not know him or who did not care to think of him in that way, might have remained at least partially ignorant of his religious and political views.

Holbach's coterie met for thirty years, from the early 1750's until about 1780. During that time his first wife died and he married her younger sister, Charlotte Suzanne d'Aine, with whom he had four children. Holbach wrote prolificly throughout this time. According to Vercruysse, Holbach authored or coauthored over fifty books and over four hundred articles. He died in 1789.