In his previous lifetimes the Buddha sometimes breaks the precepts: Sometimes he kills, sometimes he steals, sometimes he has illicit sex, sometimes he takes alcohol. But he never lies.

"Virtue, in Buddhism, is expressed in the five precepts. Of the five, truthfulness is said to be the highest virtue because it’s only through truthfulness that you’re in a position to admit your mistakes and to learn from them. There are passages in the Canon called the Jātaka tales, which tell the stories of the Buddha in previous lifetimes. And it’s obvious from some of the stories that he’s still learning the ropes, because sometimes he breaks the precepts: Sometimes he kills, sometimes he steals, sometimes he has illicit sex, sometimes he takes alcohol. But he never lies. Ever. For him, that’s the most important precept. Because after all, if you lie to someone, the misunderstanding you create can have a bad effect not only in this lifetime but also into future lifetimes. And as the Buddha says, if you feel no shame at telling a deliberate lie, there’s no evil you’re incapable of doing."

~ Thanissaro Bhikkhu "The Five Faculties: Putting Wisdom in Charge of the Mind"