The placement of adjectives in French is actually a lot more fluid than grammar books and French teachers usually let on.
For one thing, you won't get very far in poetry or in journalistic texts before you come across an adjective before the noun that you would expect to find after the noun. And although you can congratulate yourself for spotting such an anomaly by letting out a loud 'tssk!', you should realize, preferably before you send off a letter of complaint to the editor of the newspaper you're reading, that such 'mistakes' are actually legitimate stylish devices.
The poet Charles Baudelaire doesn't hesitate to begin a poem:
Generally, you can only invert the adjective like this if you are trying to create a high-impact emotional statement, as Baudelaire is doing here in expressing his absolute terror at the coming of winter. Generally, you can only do it with strong adjectives that express an emotion of some kind. Generally, though, students of French, even when they meet these criteria, rarely get away with it, however beautiful and poetic the effect. Your teacher will assume your genius is just a mistake (a common reaction to genius). You have to be the right person before you can break the rules, just as you have to be Jackson Pollock to become famous for spilling paint.
For another thing, adjectives that normally go before a noun usually follow the noun if they are preceded by a long adverb (but not if preceded by a short adverb). For example,