Ivory and Jhabvala imagine a “typical” gala Parisian garden party circa 1784. It was hosted by the Marquis de Lafayette for Thomas, then acting as American ambassador.
Though de Lafayette was philosophically democratic, he was required to cultivate relationships with the Parisian fashionistas and aristocratic hedonism of pre-revolutionary France.
The gala is fluff meant only to encourage Jefferson and Maria Cosway’s tête-à-tête, at the start of their romance.
See James Ivory. Jefferson Paris (1995). Screenplay by Ruth Prawer Jhabvala.