On 13 July 1793, moments after the assassination of Jean-Paul Marat by Charlotte Corday, Pelletan was present at the crime scene.

Following the death of 10-year-old Louis XVII on 8 June 1795, he was responsible for performing the autopsy.

While chief surgeon at the Hôtel-Dieu, Pelletan was involved in a case of misdiagnosis that led to the death of a patient.

An opportunistic Guillaume Dupuytren (1777–1835) informed the personal physician of Tsar Alexander of the situation, which triggered an investigation into the matter.

Because of the mistake, on 6 September 1815, Dupuytren was named as Pelletan's replacement as chief-surgeon at the Hôtel-Dieu.