During the 'July Monarchy' (1830-1848) Louis-Philippe, following the practice of his predecessors, began staying at Saint-Cloud. After the fall of Louis-Philippe in 1848 the Pavillon de Breteuil, like the Château de Saint-Cloud, came under the care of the Ministry of Public Works. During the four years that followed, just before the re-establishment of the Empire, various attempts were made by the Ministry to let the property, which was described as "a country house with garden and outbuildings". The letting, which included furnishings, was put up for auction.

Of those who rented the Pavillon the most notable was the Princesse Mathilde Bonaparte, daughter of King Jérôme de Westphalia. First cousin of the Prince Louis-Napoléon, whom she nearly married, the Princesse Mathilde was separated from her husband Prince Anatole Demidoff and lived in Paris during the last years of the reign of Louis-Philippe. When Louis-Napoléon became President the salon of the Princesse Mathilde rapidly became a celebrated venue of writers and artists. Each summer, from 1849 to 1853, she set up house at the Pavillon de Breteuil. According to her biographer, Joachim Kühn: "Mathilde lived at the Pavillon de Breteuil surrounded by her closest friends. She set up a boudoir with soft cushions and delicate porcelain where she read the latest novels and poems. Under the roof she made a workshop with walls hung with textiles and covered with paintings and sketches. There she painted with the painter Giraud, in the corner Nieuwerkerke modelled a bust while one of the ladies present read aloud. In the afternoon Nieuwerkerke would take her riding in a carriage through the nearby woods of Meudon, Marnes, Ville d'Avray or Versailles. In the evenings she would often receive visits; Exelmans, Castellanne, Prince Lucien Murat would bring all the latest news from Paris..." Other visitors would have been Saint-Arnaud, Alexandre Dumas, and Doctor Véron; this last was famous for his pills and later became Director of the Opera. Just a few steps away at the Château de Saint-Cloud was the Prince-President who gave fêtes at which Mathilde presided. At the re-establishment of the Empire in 1853 Mathilde was still to be found at the Pavillon de Breteuil, but this was to be her last visit. The only subsequent mention we have of the inhabitants of the Pavillon de Breteuil before the fall of the Empire in 1870 is a brief mention in the Moniteur Universel of 3 October 1869: "... the Château de Breteuil inhabited in turn by the Princesse Mathilde, the Grand-Duchesse de Bade and the Grand-Duchesse Marie de Russie...".