I include this here under Napoleon Bonaparte because that seems to be the most common attribution, and probably the best answer to go for if you're asked about this line in a quiz. But this remark has been traced in print to the year 1777, when Napoleon was only eight years old.
The Quote Investigator (QI) located this assertion in a collection of philosophical thoughts, published in that year, entitled Pensées Nouvelles et Philosophiques (New Thoughts and Philosophies). The words were attributed to the prominent author Bernard Le Bovier de Fontenelle, who had by this time been dead for twenty years. The quote reads "Du sublime au ridicule, disait Fontenelle, il n’y a qu’un pas: de la raillerie à l’insulte il y en a encore moins." This can be translated into English as "From the sublime to the ridiculous, said Fontenelle, it is only one step: from raillery to insult there is even less."
The earliest attribution to Napoelon, located by the QI, comes from a memoir published in 1815 by Dominique-Georges-Frédéric Dufour de Pradt, Napoleon's former secretary. De Pradt describes how Napoleon, after his defeat in Russia (in 1812), repeated two or three times, in his presence: "du sublime au ridicule il n’y a qu’un pas".
Even before this, a similar sentiment had appeared in English, in Thomas Paine's The Age of Reason (1795): "The sublime and the ridiculous are often so nearly related, that it is difficult to class them separately. One step above the sublime, makes the ridiculous; and one step above the ridiculous, makes the sublime again." And later in the same work: "When authors and critics talk of the sublime, they see not how nearly it borders on the ridiculous."
In conclusion: we have reliable evidence that Napoleon did use this expression; but he clearly wasn't the first person to do so. It was, the QI notes, already in common usage in France; and it had even found its way into English. The evidence suggests that it was coined at least as early as the mid-eighteenth century, quite possibly by Fontenelle; one even wonders whether we might be justified in describing it as a French proverb.
© Haydn Thompson 2019