I saw this story on @HistoryWeird's blog here. The original source was a Telegram to the French Ambassador in London, July 28, 1835.
"In July 1835 assassins targeted the French king, Louis-Philippe, as he reviewed troops in Paris. News of the attempt on the king’s life was conveyed by telegram to the French ambassador:
"'An atrocious act was attempted this morning during the review [of troops]. The King of the French was not touched, although his horse was killed. None of the Princes were wounded. The Duke of Treviso was killed. Several guards, aides-de-camp and National Guardsmen were killed or wounded. The deed was committed by means of an infernal machine placed behind a window… Paris is quiet and indignant.'
The aftermath of the “infernal machine”: dead and injured soldiers and horses strewn across the Boulevard du Temple.
"The leader of this bizarre assassination attempt was Giuseppe Marco Fieschi. A former soldier and serial thief, Fieschi served several years’ hard labour in his native Corsica before escaping to Paris. Once in the capital Fieschi took up with political radicals and began to plot the king’s murder. But unlike John Wilkes Booth and Lee Harvey Oswald, Fieschi and his accomplices left nothing to chance. They designed and constructed their 'infernal machine': a battery of 20 muskets attached to a wooden frame, all rigged to fire simultaneously. The machine was aimed at the royal party from an elevated window overlooking the Boulevard du Temple.
"The firing of the 'infernal machine' proved devastating: it killed 18 soldiers, including a marshal and former prime minister. Louis-Philippe and other royals were not seriously injured, however one shot grazed the king’s temple and another struck his horse. Backfiring from the 'infernal machine' also took its toll on Fieschi, who was hit in the head with shrapnel and badly burned. He was quickly captured and given medical attention, then put on trial for regicide. Fieschi and two of his accomplices were guillotined in February 1836."
You know that this whole unlikely instance is the result of one of the assassins saying during the planning stage, "20 guns? Nothing can go wrong now." Or "20 guns? How could it possibly fail?" You know someone tempted fate with this one.