They torched, burned, and looted. When they got bored with that, the elites and leaders such as Robespierre started dressing in white robes, and declared themselves gods. They demanded a "Newspeak" language, and changed the meaning of words. They even reamed the days of the week and the months of the year. EVERYTHING had to be "Revolutionary." Anyone who didn't go along soon found out their fate.
They started murdering the "Counter-Revolutionaries." These were anyone, from the lowest peasant to the intellectuals - and even children. The guillotines ran day and night, seven days a weeks. The streets literally ran red with blood.
It was all so much fun. Until the leader of the Revolution, Robespierre, was himself declared "Counter-Revolutionary" and sent to the guillotine himself.
I don't recall exactly what the rationale was... it just was "'cause we say so"...