The French Republican calendar was base-ten. A month had 3 decades, aka 3 weeks of 10 days, each day 10hrs, etc.
"In revolutionary France, an hour was almost twice as long, a minute slightly longer, and a second slightly shorter [...] the calendar intentionally disrupted “church-attending practices, since it presented both practical and cognitive difficulties in keeping up with the traditional, sacred seven-day cycle.”

So they'd need ~3hrs sleep, and work for ~4hrs per day. It reflects some economical notion of time spending. But they also had to work for 9 days before getting 1 day rest, that is so long.