Well, the Storming of the Bastille took place in 1789, which could be a potential hint to the length. 1789 meters is 5869.42 feet.
But given that it was Chris who has given the clue, I wonder if it was his reference. Marie Antoinette, the wife of King Louis XVI at the time, had supposedly said, "Let them eat cake," after learning that the peasants had no bread to eat. With cake (not cake as we know it today. It's more of a heavier bread made with lots of eggs and butter) being more expensive than regular bread, it made people think Marie Antoinette never cared for the peasants at all.
She was also known as a heavy spender and was nicknamed "Madame Deficit." Her extreme spending was what many people believed to have led to the financial crisis of France. Perhaps the clue is alluding that this coaster is going to have a high price tag (but obviously an affordable one. Don't want to start that arguing again).
Thank you World History class. Who would've guessed that I might need to know this stuff for the summer?