This is the night that Georgina comes over to Serenas house to crash the dinner with Serenas mom and brother. Yet when Rufus meets lily on the street to talk about Jenny, he takes the schedule she has for the day and makes a comment about where she can fit in a talk. On that schedule it says "Jacques Louis-dinner with William and Charlie. Drinks after" at 8pm. No where does it say family dinner.
When Chuck calls Serena on her cell phone, she answers, "Salut, Chuck", however in French, you answer the phone with an "âllo", and "salut" is an informal greeting face-to-face.