The Council of Orange was an outgrowth of the controversy between Augustine and Pelagius. This controversy had to do with degree to which a human being is responsible for his or her own salvation, and the role of the grace of God in bringing about salvation. The Pelagians held that human beings are born in a state of innocence, i.e., that there is no such thing as a sinful nature or original sin.
As a result of this view, they held that a state of sinless perfection was achievable in this life. The Council of Orange dealt with the Semi-Pelagian doctrine that the human race, though fallen and possessed of a sinful nature, is still "good" enough to able to lay hold of the grace of God through an act of unredeemed human will.
There were 25 Canons adopted. Here are the first 5:
CANON 1. If anyone denies that it is the whole man, that is, both body and soul, that was "changed for the worse" through the offense of Adam’s sin, but believes that the freedom of the soul remains unimpaired and that only the body is subject to corruption, he is deceived by the error of Pelagius and contradicts the scripture which says, "The soul that sins shall die" (Ezek. 18:20); and, "Do you not know that if you yield yourselves to anyone as obedient slaves, you are the slaves of the one whom you obey?" (Rom. 6:16); and, "For whatever overcomes a man, to that he is enslaved" (2 Pet. 2:19).
CANON 2. If anyone asserts that Adam’s sin affected him alone and not his descendants also, or at least if he declares that it is only the death of the body which is the punishment for sin, and not also that sin, which is the death of the soul, passed through one man to the whole human race, he does injustice to God and contradicts the Apostle, who says, "Therefore as sin came into the world through one man and death through sin, and so death spread to all men because all men sinned" (Rom. 5:12).
CANON 3. If anyone says that the grace of God can be conferred as a result of human prayer, but that it is not grace itself which makes us pray to God, he contradicts the prophet Isaiah, or the Apostle who says the same thing, "I have been found by those who did not seek me; I have shown myself to those who did not ask for me" (Rom 10:20, quoting Isa. 65:1).
CANON 4. If anyone maintains that God awaits our will to be cleansed from sin, but does not confess that even our will to be cleansed comes to us through the infusion and working of the Holy Spirit, he resists the Holy Spirit himself who says through Solomon, "The will is prepared by the Lord" (Prov. 8:35, LXX), and the salutary word of the Apostle, "For God is at work in you, both to will and to work for his good pleasure" (Phil. 2:13).
CANON 5. If anyone says that not only the increase of faith but also its beginning and the very desire for faith, by which we believe in Him who justifies the ungodly and comes to the regeneration of holy baptism — if anyone says that this belongs to us by nature and not by a gift of grace, that is, by the inspiration of the Holy Spirit amending our will and turning it from unbelief to faith and from godlessness to godliness, it is proof that he is opposed to the teaching of the Apostles, for blessed Paul says, "And I am sure that he who began a good work in you will bring it to completion at the day of Jesus Christ" (Phil. 1:6). And again, "For by grace you have been saved through faith; and this is not your own doing, it is the gift of God" (Eph. 2:8). For those who state that the faith by which we believe in God is natural make all who are separated from the Church of Christ by definition in some measure believers.
The entire set of Canons can be read here.