Scene: This slip-up is found after Satine blows off the Duke to be with Christian. They are kissing on the balcony hiding from the Duke and Zidler. Zidler tells the Duke that the dinner is ready for them, and the Duke says you might as well eat it yourself. Then Zidler spots Christian and Satine kissing on the balcony.

Slip-up: When Christian is leaving he looks straight at Satine and there is nothing unusual about his face. However, he begins to leave and turns back and asks "What time?" and there is clearly several lipstick marks on his face.