In 1765, named the heir of his paternal aunt, Élisabeth Alexandrine de Bourbon, Louis Joseph received generous pensions which Élisabeth Alexandrine had in turn acquired from her cousin, Louise-Françoise de Bourbon. In that same year, Louis Joseph repurchased the Palais Bourbon, previously owned by his family, from King Louis XV, and decided to rebuild it from a country house into a monumental palace, in the new Classical Revival style. With this in mind, he purchased the neighboring "Hôtel de Lassay" in 1768, planning to make the two buildings into one. However, the palace was only finished at the end of the 1780s, when the French Revolution later swept away the old regime. He then moved from the Hôtel de Condé, where he was born, to the Palais Bourbon. The former residence was later sold to King Louis XV in 1770, becoming the subsequent site of the Odéon Theatre. Among other estates, Louis Joseph also inherited the famous Château de Chantilly, the main seat of the Condé line. At Chantilly, the prince conducted a number of improvements and embellishments in the years before the French Revolution. He had the "Château d'Enghien" built on the grounds of the estate to house guests when the prince entertained at Chantilly. It was constructed in 1769 by the architect, Jean François Leroy, and was later renamed the Château d'Enghien in honour of his grandson, Louis Antoine de Bourbon, Duke of Enghien, who was born at Chantilly in 1772. He also commissioned a large garden in the English style as well as an "hameau", much like the contemporary one that Queen Marie Antoinette had created at Versailles and at the "Petit Trianon" château.