Because of the close connections of the Catholic establishment in France with the kings and nobility, the Revolution was strongly anti-Church, and children were no longer given saints' names. But they had to call the poor little guys SOMETHING, with the result that reminds me a lot of baby names in the 1960s, like Moon Unit, Rain, and River. (This is why the heroine of Les Miserables gets named Fleurette, by the way).
Because so many days, before the Revolution, were saints' days (today was St. Justus of Rome, by the way), the Revolutionary Government decreed that every day in the New Calendar (1793 - the year of the Terror - was the Year One) was named for something "natural", so you had things like Carrot Day, Broccoli Day, Rabbit Day, and Shovel Day (Shovel Day was the 20th of December. 25 December was Dog Day.)
I don't know why this entertains me the way it does, but of course, since Benjamin January belongs to the immediate post-Revolution generation, I amuse myself by giving some characters what are clearly names from well-meaning parents wanting to celebrate the 14th of July or Civilization, or whose kids were born on Wild Ginger Day. The lucky ones just got named after Greek or Roman heroes, like Brutus or Lycurgus. (And probably changed their names to Pierre the minute they could.)