In the novel Murder on the Links, Monsieur Hautet is the Juge d'instruction or Examining Magistrate responsible for investigating the murder of Paul Renauld in Merlinville-sur-Mer. He knows of Hercule Poirot and his reputation and courteously requests Poirot to help in the investigation and join him in interviewing the witnesses.
As the Examining Magistrate, Hautet is actually senior to the police and has the authority to direct the police to investigate specific aspects of the case. Thus Lucien Bex, the local police officer, defers to him. However Monsieur Giraud from the Sûreté is dismissive of him and treats him with discourtesy. He did not, for example, report to Hautet on first arriving from Merlinville. "A fig for the magistrate," he says. This antagonised Hautet, and he proceeds to interview witnesses with Bex and Poirot but leaving Giraud alone. "Monsieur Giraud has shown clearly that he prefers to conduct the case in his own way," he tells Poirot.
Hautet is described as a tall gaunt man with piercing dark eyes. He had a neatly cut grey beard which he had "the habit of caressing as he talked".