Short answers, pulled from the story.
13 Vendémiaire was a battle fought on the 5th of October 1795 between French Revolutionary troops and Royalist forces in the streets of Paris. It was part of establishing the Directory as France's new government, and it was a major factor in the rapid advancement of Republican General Napoleon Bonaparte's career.
The battle took place on 13 Vendémiaire, Year 4 of the French Republican Calendar, which corresponds to the 5th of October 1795.
Napoleon Bonaparte directed the Republican artillery after joining Paul François Jean Nicolas Barras's forces on condition of complete freedom of movement. He ordered Joachim Murat to retrieve 40 cannon from the plain of Sablons and positioned them in commanding areas to defend the Convention.
Around three hundred Royalists were killed during the two-hour engagement in the streets of Paris. The Republican defenders had been outnumbered approximately six to one before the major Royalist assault of 7,000 men was repulsed.
The phrase comes from Scottish historian Thomas Carlyle, who wrote that Bonaparte gave his opponents a Whiff of Grapeshot and that this is what blew the French Revolution into space. The words are often mistakenly credited to Bonaparte himself, but they were probably Carlyle's own.
Bonaparte was appointed General in Chief of the Army of the Interior and quickly promoted to Général de Division. Within five months he was given command of the French army operating in Italy, and the defeated Royalists nicknamed him Général Vendémiaire, a title he later called his first title of glory.