Benjamin Franklin was never president, but he held many other important jobs, including that of minister to France during the Revolutionary War. Franklin was in Paris in 1778, when he received a letter from a stranger supposedly named Charles de Weissenstein that proposed a clandestine meeting at Notre Dame cathedral to arrange for ending the war. Weissenstein made it clear that King George would never allow the Americans to be free of the British Empire, but might accede to some colonial demands, which Franklin could convey to him in a very suspicious cloak-and-dagger fashion. The instructions for dropping off the document were very explicit, and might remind you of a poorly-written spy novel.
“If the Iron Gates above mentioned happen to be shut, you will find him in the aisle of the right hand on going in, on the same side (if I mistake not) where the huge statue of St. Christopher is. For your more certain guidance, I have desired him to stick a rose, either in his hat, which he will hold in his hand up to his face, or else in the buttonhole of his waistcoat, either of which will be remarkable enough, with the other circumstances.”
From the snarky response Franklin wrote, you might imagine that he first had a big laugh at the very idea. Read the whole story of Ben Franklin's brush with a spy at Plodding Through the Presidents. -via Strange Company