"The President's Hat" is a novel by French author Antoine Laurain. The story revolves around a simple man named Daniel Mercier, who finds a hat belonging to François Mitterrand, the former President of France. When Daniel wears the hat, he experiences a series of unexpected events that change his life. As Daniel navigates his newfound confidence and fortune, the hat influences his actions and decisions. The narrative explores themes of power, identity, and the impact of chance encounters, all while providing a whimsical look at how a single object can alter one's destiny.