Because Tropic of Cancer doesn't have a linear narrative, it's not going to fit exactly into each stage. But we love trying to put square pegs into circular holes, so here's our shot.
Now, we know that Henry is wretched for almost the entire novel. But he never lets that get in the way of a good time. (Now there's a lesson for us all.) He does begin the book in a lice-ridden house, believing that the "The world is a cancer eating itself away" (1.8). So it's not exactly cheery. He is, however, called to write—and that is a huge motivator.
Never mind that Henry's idea of "success" is scoring a prostitute who doesn't have the clap or getting a piece of cheese for dinner. He is clearly proud of the careful balancing act he is pulling off by rotating meals at various people's houses and getting leftover prostitutes from his friends. He has found his rhythm.
Okay, so now he's hungry and has kind of used up all of his friend's good will. He has done everything from proofreading to pimping to try to get by. Now he has to accept humankind's most challenging mission: teaching. What better way to while away the hours than to sequester yourself in a backwater town in eastern France known for making a particularly strong mustard relish?
Dijon is both the best and worst thing that ever happens to Henry. Though Dijon immediately strikes him as "silent, empty gloom" (13.16) and the school sends a "shudder" through him, first impressions can be very overrated. Well, they aren't. He tells us: "After a week it seemed like I had been here all of my life. It was like a bloody fucking nightmare that you just can't throw off. Used to fall into a coma just thinking about it" (13.35). He has clearly hit rock bottom.
Being back in Paris is like a rebirth unto itself. "It was spring before I managed to escape from the penitentiary, and only then by a stroke of fortune" (14.1). Now he returns to the same Paris he left, only his friends are in even bigger messes. But Henry is on the mend. His charitable effort of getting Fillmore out of town nets him a sweet pile of cash and reminds him that he really is happy in Paris. So the riches aren't only the pockets full of francs he now has, but the feeling that "After everything had quietly sifted through my head a great peace came over me" (15.111).