The Chalk Circle Man by Fred Vargas

In a city haunted by mysterious blue chalk circles appearing overnight on its streets, each encircling a seemingly random object, the eccentric and intuitive Commissaire Adamsberg is drawn into a perplexing investigation. As the circles grow in number and complexity, they become the harbinger of a series of gruesome murders. Adamsberg, known for his unconventional methods and keen instincts, must untangle the web of clues and delve into the psyche of a disturbed mind to prevent further bloodshed. With a blend of suspense, wit, and psychological depth, the narrative explores the thin line between madness and genius, challenging the detective to confront his own demons while unraveling the mystery.