He voted in favour of the death sentence for Louis XVI.[5][6] Later, in the events leading up to the Reign of Terror, he was arrested by Girondist supporters and was imprisoned in Caen for two months.[citation needed]
During his tenure in National Convention, Romme served in the Committee of Public Education [fr] (Comité de l’instruction Publique), where he presented his report on the republican calendar on 17 September 1793 and then developed an agricultural almanac based on the new calendar.[7] Aware of their military importance, he was also an early supporter of semaphore telegraphs.[citation needed] He served as president of the Convention from 21 November to 6 December 1793. [citation needed]
Because he was on an assignment to organise gun production for the navy, he had no hand in the coup of 9 Thermidoran II (27 July 1794), which resulted in the fall of the Robespierre (and ultimately led to the return of the Girondists).[citation needed]
When rioting sans-culottes, demanding bread and the Jacobin constitution, violently occupied the Convention on 1 Prairialan III (20 May 1795), Romme supported their demands. This insurrection was quickly put down however, and he and other Montagnards were arrested.[citation needed] While waiting for their trial, the defendants agreed to commit suicide in case of a death sentence.[citation needed]
On 29 Prairial (17 June), Paris, France, Romme and five others were sentenced to the guillotine. With a knife hidden by Jean-Marie Goujon, he stabbed himself repeatedly while on the staircase leading from the courtroom, and died — his last words are reported to have been "I die for the republic".[citation needed]
In Romme le Montagnard (1833), Marc de Vissac described Romme as a small, awkward and clumsy man with an ill complexion and a dull orator but also as possessing a pleasant and instructive style of conversation.[citation needed]