Jean Valjean commits a petty crime, stealing a loaf of bread to feed his sisters hungry family, and is sent to a harsh prison for his crime. When he gets out, he is not prepared to support himself and he commits another crime, against Bishop Digne.
Valjean tries to steal from the Bishop, but in return, he is not punished, but given another chance by the compassionate Bishop. The only condition on his second chance is to use it to improve his life.
Valjean goes to a small town Montreuil sur Mer, where he uses his new found wealth to help the town by rebuilding its industries providing many jobs for the people. He also saves the daughter of the prostitute, Fantine, taking her into his house as his own daughter.
Jean Valjean becomes mayor of the small town and is gracious and generous to all its citizens. He is a much loved mayor, not pretentious, but a humble servant of the people.
In all of his actions, he is generous and kind, especially to Cosette.
Look up "humanitarian"--you might have a problem finding evidence because you're not sure what to look for. So look up the word, and see is you can find evidence the ties Jean Valjean to each of the three separate definitions of humanitarian. You can do this search a number of ways. One way is to first, get three highlighters, and assign each definition to its own highlighter. Then one at a time, go through the entire book highlight, say in blue, words that convey the first definition. The use the pink highlighter and go through whole book and highlight words of the second definition, and then use the yellow in the same way for the third. Then look at the blue words and start grouping them based on how they show the first definition in some way. Then when you've had enough blue thinking, switch over and do the pink words. and later then go back to blue or do the yellow words.
You'll find that the book will tell you the answer.