Also in the USA. We call it "prison labor", and over 1% of our adult population is "under correctional control."
Approximately two-thirds (about 61% to over 65%) of the 1.2 million people incarcerated in US state and federal prisons are employed in prison labor, totaling around 800,000 workers. These workers often perform maintenance tasks for, on average, 13 to 52 cents per hour, with many facing forced labor conditions https://www.epi.org/publication/rooted-racism-prison-labor/#...
There are also slaves you see outside your window without recognizing them as such. Homeless people are sometimes exploited by gang members who enslave them to either pimp themselves out or sell drugs.
One of the side effects of a society tolerating thousands of people living in nylon tarps with no real safety net.
I'm against for-profit prisons, but equating people who commit crimes and end up in prison and are forced to work as part of their sentence, to people who have committed no crimes is a bit ridiculous.