I'm currently listening to the Audiobook version of Christopher Hitchens: Thomas Paine's Rights of Man.
There it is mentioned that when in french prison Paine was sentenced to death, however his warder marked the wrong side of the door and because of that he wasn't executed the following day and could later be released when Robespierres regime ultimately fell a few days later. Hitchens credits this lucky stroke to the stupidity of his warder.
While certainly possible that his warder just made a dumb mistake, are there be alternative explanations as to why he wasn't executed which could be more likely?
It seems to me that executing one of heroes of the American Revolution might not have been the smartest thing to do for the young French Republic.
Since I'm listening to the Audiobook version I don't see the footnotes Hitchens has for this, but what I could find so far was the letter in which Paine describes the anecdote:
When persons by scores and hundreds were to be taken out of prison for the guillotine, it was always done in the night, and those who performed that office had a private mark or signal by which they knew what rooms to go to, and what number to take. We, as I have said, were four, and the door of our room was marked unobserved by us, with that number in chalk; but it happened, if happening is a proper word, that the mark was put on when the door was open and flat against the wall, and thereby came on the inside when we shut it at night, and the destroying angel passed by it.
It's impossible for him to have been sentenced to death before this story plays out. He was imprisoned in Paris, and anyone who was being judged by the Parisian revolutionary tribunal would be kept in a prison called the Conciergerie. After sentencing, the condemned would be kept in separate cells away from the other prisoners. There would be no need to mark any doors and no way to accidentally leave someone behind.
Paine was held in Luxembourg prison, and it's just not possible that he would have already been sentenced. What he probably means is that a decision had been made to transfer him to the Conciergerie in preparation for the trial, which he refers to as being taken to the guillotine as a critique of the legal system of the time.
During the spring of 1794 some prisoners started denouncing other prisoners, claiming that they were involved in plots against the government. The Luxembourg was one of the prisons where this happened, and in July a group of 157 prisoners were executed as a result of these denunciations. This it probably the event Paine refers to, even though he doesn't state the exact date, and the number is slightly different. The executions also didn't happen all at once on the next day. The order to extract the prisoners from Luxembourg was given by the prosecutor Fouquier-Tinville (himself following the orders of the committee of public safety) on 18 Messidor, and the trials took place on the 19th, 21st and 22nd of the same month.
Thomas Paine is not on any of the acts of accusation for these three groups of prisoners, and those three documents were directly based on the lists of prisoners to move from the Luxembourg. In volume 4 of his Histoire du tribunal révolutionnaire de Paris Henri Wallon discusses the discrepancies between the acts of accusation and the order to extract the prisoners, and he doesn't name anyone who was supposed to be moved but couldn't be located.