How does Le Brun get Thisbe as his assistant?

Le Brun tells Lucien that he requires two dollars a day as payment and a room for his assistant. Lucien is reluctant to pay for an assistant, so Le Brun suggests that Thisbe be his assistant. When Lucien and Le Brun approach Sylvie about the matter, she refuses. Le Brun says he will leave, so Sylvie has to give in and allow Thisbe to be his assistant.