- "Marat was one of my patients. I was treating a horrible skin condition he developed while hiding in the sewers. I'll write you the address if you think you might find something there that'll lead to the swine who did this. Marat spoke often of how he might be made a sacrifice for his people. His prophecy is fulfilled."
- ―Brousseau upon being questioned by Arno Dorian, 1793.[src]
During the French Revolution, Brousseau treated the skilled physician and leading Jacobin Jean-Paul Marat. Marat had developed a chronic skin disease after hiding from his enemies in the sewers of Paris, and took medicinal baths with Brousseau's tonics. After Marat was assassinated in July 1793, Arno Dorian investigated the murder. Upon being questioned by Arno, Brousseau gave him the address of the sewer in which Marat had hidden, hoping that the killer would be found.