About the book (from Wikipedia):
Pippin IV explores the life of Pippin Héristal, an amateur astronomer in 1950s France, who is suddenly proclaimed the King of France. Unknowingly appointed to give the Communists a monarchy to revolt against, Pippin is chosen because he was descended from the famous king Charlemagne. Unhappy with his lack of privacy, alteration of family life, uncomfortable housings at the Palace of Versailles and his lack of power as a constitutional monarch, the protagonist spends a portion of the novel dressing up as a commoner, often riding a motorscooter, to avoid the constrained life of a king. Pippin eventually receives his wish of dethronement after the people of France enact the rebellion Pippin’s kingship was destined to receive. He returns to his home in Paris to find that nothing has really changed.