A combination
banknote, share
certificate, food
voucher,
identity card,
confession, and
will in pre- and post-Revolutionary
France.
Originally it was a bonus issue of stocks in Paris commodity markets, redeemable for food if any food ever appeared in the market (inspired by the royal comment "Let them eat the CAC-40"); after the Revolution ownership of assignats was compulsory, and each came with several removable coupons.
For each coupon handed in, the head of the household could save his wife, a child, or any other member of his household from the guillotine; or by handing in all his coupons at once he could save himself.
Failure to produce an assignat on demand, or producing a mutilated one, was a capital offence. Unfortunately, clipping the coupons was regarded as mutilation.
At the height of the Terror, to save work in police stations, they were pre-signed and pre-printed with a range of crimes and a box against each, which stall-holders would tick depending on the value of the transaction. For example, to get a cauliflower you confessed to aggravated assault; to get a nice piece of haddock or cod for your tea you asked the fishmonger to tick setting fire to a hayrick; and to get a king-sized tub of double-choc chocolate-chip ice-cream with whipped cream, maple syrup, and wafers, you admitted being Charlotte Corday.