Jean Valjean is often referred to as a Christ-like character, and there are several examples of how this comparison is drawn. The one difference, to note immediately, is that Jean Valjean has a moment of conversion, which takes place just after the Bishop forgives him and gives the silver he stole as a gift and a reminder to become "an honest man."
After his conversion, Jean Valjean becomes a portrait of unconditional love. First, he attempts to save Fantine, and when he cannot, he promises to take care of her daughter. Cosette, unaware of Valjean's sacrifice (the fact that he is an ex-convict on the run and living under an assumed identity) could represent humanity. Valjean's protection and love of her is one that stems from pure mercy, grace, and love, and though she accepts it, she cannot fully understand its depth. Even when she falls in love with Marius, Valjean continues to sacrifice his own desires, and saves Marius so he can have Cosette.
In addition to saving Cosette and Marius (literally), as M. the Mayor, Valjean essentially saves society. He provides jobs and an income for many who would otherwise be very poor and starving. Think also of the scene in which he saves Fauchelevant from the fallen cart by lifting the cart on his shoulders. The picture of this very scene is reminiscent of Christ carrying his cross.
Post-conversion through the Bishop of Deign, Valjean is portrayed as a sinless, merciful, protector and providor. All of these qualities are similar to qualities associated with Jesus Christ