Breteuil was born in 1730 at the Château d'Azay-le-Ferron (Indre) into a well-connected aristocratic family: one of his relations was confessor to the king's cousin and another was the famed mathematician and linguist Émilie, marquise du Châtelet-Laumont.

Two years later in 1760 he was sent to St Petersburg as the French ambassador to Imperial Russia, where he arranged to be temporarily absent from his post at the time of the palace revolution by which Catherine II was placed on the throne.

Breteuil's time as Household Minister corresponded with the infamous Affair of the Diamond Necklace, which pitted him against his enemy, the Cardinal de Rohan.

They then proposed burning Marie Antoinette in effigy, but the troops were deployed and they dispersed the crowds with great bloodshed in the Place de la Grèe.

Though Breteuil was disgusted with French politics at the time, he remained absolutely loyal to the Monarchy, despite his liberal views on social culture.

A carefully orchestrated plan was drawn-up by Breteuil, the duchesse de Polignac, the King's brother the comte d'Artois and with the support of Marie-Antoinette.

The duchesse de Polignac escaped to Switzerland, and Louis XVI sent the comte d'Artois abroad to save him from assassination.

[4] At Soleure, in November 1790, he received from Louis XVI exclusive powers to negotiate with the European courts,[5] and in his efforts to check the ill-advised diplomacy of the émigré princes, he soon brought himself into opposition with his old rival Calonne, who held a chief place in their councils.

In coordination with Marie Antoinette's favourite, the Swedish count Axel von Fersen, Breteuil organised the royal family's escape from Paris in 1791, garnering support from King Gustav III of Sweden.

After the failure of the flight to Varennes, Breteuil received instructions from Louis XVI, designed to restore amicable relations with the princes.

His distrust of the king's brothers and his defense of Louis XVI's prerogative were to some extent justified, but his intransigent attitude towards these princes emphasized the dissensions of the royal family in the eyes of foreign sovereigns, who looked on the comte de Provence as the natural representative of his brother and found a pretext for non-interference on Louis's behalf in the contradictory statements of the negotiators.

Breteuil himself was the object of violent attacks from the party of the princes, who asserted that he persisted in exercising powers which had been revoked by Louis XVI.

Breteuil's secret correspondence with Louis XVI and Marie Antoinette was discovered in an Austrian castle by historian Munro Price.

His findings were presented in The Fall of the French Monarchy: Louis XVI, Marie-Antoinette and the baron de Breteuil, (sometimes titled The Road from Versailles).