Steuval's bookbinder and engraver was arrested on suspicion of murder, but Maigret doubts his guilt, although it is certain that he and his accomplice burned a body in his house. One morning, in the park, Madame Maigret meets a young Italian woman wearing a striking white hat. The Commissioner's wife finds out that this white hat belongs to the famous Countess Panetti, who is found dead in the Marne. Now, thanks to his wife, Maigret also succeeds in establishing the link between Steuval's death and the Countess's murder. Based on the 34th Maigret novel L'amie de Mme Maigret (1949), which appeared in German first as Frau Maigret als Detektiv and later in a new translation as Madame Maigrets Freundin erschien.