I bet it's a translation of Bastiat's dated and somewhat understated language. Let me explain it more simply:
For a while, French factories SEEMED to be thriving, because orders were pouring in from France and all over Europe. But what was really happening was that the buyers were anticipating that the currency would collapse, so they would rather have goods than soon-to-be-worthless paper.
Once the currency starts nosediving in earnest, so does business, in part because inflation starts getting booked as a false "profit". Imagine that you were a merchant, and you bought goods for $100 and sold them for $200. You've made a 100% profit! OR HAVE YOU?! If inflation is very steep, you might very well have sold at a LOSS! Because you'd have to replenish your stock at, say, $250. You're actually losing money, but on your books it "looks" like a profit! (and you are taxed accordingly!)
When he said "limited prosperity", more likely that was an understatement (perhaps politically-motivated, to avoid offending the wrong people!) for saying widespread bankruptcy.
Another thing that does businesses in during steep inflation, is that as prices rise, consumer preferences shift. Someone in the wrong business will go bankrupt as consumers switch to more basic necessities. As a result, a lot of businesses fail during steep inflations.