Madame du Barry
Béatrix continued her attempts to succeed as official royal mistress and reportedly believed herself to be near success when Madame du Barry attained the position in 1768. Béatrix in collaboration with her sister-in-law the Duchesse de Choiseul and the Princess of Beauvau, (referred to as "the Choiseul-women") led the noblewomen first in their efforts to prevent Madame du Barry from being presented at court and then to ostracize her from it. One idea, suggested by the Mesdames de France, was for the king to marry to either the Princess of Lamballe or Archduchess Maria Elisabeth of Austria, but the Choiseul party opposed a remarriage of the king, and according to the Count of Mercy-Argenteau:
"Persons in power, imagine that a queen, judicious and amiable, who would succeed in gaining the affection of her husband, might open his eyes to the irregularities and the enormous abuses which exist in all departments here, and cause much embarrassment to those who direct them. They are consequently of opinion that it behooves them to divert the mind of the King from ideas of marriage; and I have very strong proofs that Madame de Gramont, more interested than any one in the maintenance of the present abuses, has succeeded in persuading M. de Choiseul to renounce his own predilections in this affair."
After the formal introduction of Madame du Barry to court, the Choiseul-women excused themselves from the king's private suppers at the Petits Cabinets, effectively demonstrating that it was socially unacceptable for noblewomen to associate with Madame du Barry. The king defeated the boycott by enlisting initially the Marechale de Mirepoix (friend of Madame de Pompadour) and then several other noblewomen to integrate his mistress at court by acting as her companions.
When du Barry was officially accepted at court, the conflict developed into a personal feud between the king's mistress and the Choiseul party. The Duke de Lauzun was sent to mediate a message of peace from Madame du Barry to the Duke de Choiseul, but when he arrived, Choiseul was in the company of his sister and received the message "with all the haughtiness of a Minister who is harassed by women and believes that he has nothing to fear," and declared that there was "war to the knife" between him and Madame du Barry, while Béatrix "made some outrageous remarks, in which she did not spare even the King." The Comtesse de Gramont, lady-in-waiting to Marie Antoinette and the sister-in-law of Béatrix, participated in the continuing boycott and made a rude remark to du Barry, causing the king to exile the comtesse from court, creating discord between du Barry and Marie Antoinette.
During the affair regarding the Duc d'Aiguillon, she was accused of participating in a conspiracy organised by Choiseul. Mercy reported to Empress Maria Theresa that "the Duc de Choiseul had had a violent altercation with the Duc de Richelieu, owing to the latter having declared that Béatrix, while passing through Provence and Languedoc on her way to Bareges, had sought to stir up the Parliaments of those provinces against the decisions of the court in the affair of the Duc d'Aiguillon."
The conflict between du Barry and the Duke of Choiseul ultimately resulted in the dismissal and exile of Choiseul from court, for which du Barry on at least one occasion blamed Gramont:
"The conversation after dinner took a more serious turn. She spoke with a charming frankness about the Duc de Choiseul, and expressed regret for not having been on friendly terms with him; she told us of all the trouble she had taken to bring about a better understanding, and said that, had it not been for his sister, the Duchesse de Gramont, she would have succeeded in the end; she did not complain of anyone and said nothing spiteful."
