During French colonization, Saint Domingue was populated by 3 classes of inhabitants, divided by the color of their skin. The white colonists at the top, the mulattoes and free blacks in the middle; the black slaves at the bottom. The lowest class was mainly of Africans born, they outnumbered the other races by a ratio of 10 to 1. Due to poor living conditions: Overwork, inadequate food, clothing, shelter and medical care, the death rate among them were extremely high. Nearly half a million slaves died each month. To keep the balance, 400.000 black men, women and children were imported from various part of Africa. The slaves conditions in Saint Domingue were worst than in all the other colonies. It was the most brutally efficient colonies of the era.  As important as Saint Domingue was to France, the french masters did everything in their power and beyond to make sure that Saint Domingue remained the most productive in the world. Slavery was sustained by a regime of torture and terror. Planters justified their use of violence by arguing that in a society in which masters were a tiny minority, the threat of atrocities was the only way to prevent a slave insurrection.
Here's a passage from Henry Christophe's personal secretary after the independence who had been a slave for more than half of his life, describing the atrocities of the french masters towards the slaves:

"Have they not hung up men with heads downwards, drowned them in sacks, crucified them on planks, buried them alive, crushed them in motards? Have they not forced them to eat shit? And have they not flayed them with lashes, have they not cast them alive to be devoured by worms, or onto anthills, or lashed them to stakes in the swamp to be devoured by mosquitoes? Have they not thrown them into boiling cauldrons of cane syrup? Have they not put men and women inside barrels studded with spikes and rolled them down the mountains sides into the abyss? Have they not consigned these miserable blacks to man-eating dogs until the latter, sated by human flesh, left the mangled victims to finish off with bayonet and poniard."  

" They were about a hundred men and women of different ages, all occupied in digging ditches in a cane-field, the majority of them naked or covered with rags. The sun shone down with full force on their heads. Sweat rolled from all parts of their bodies. Their limbs, weighed down by the heat, fatigued with the weight of their picks and by the resistance of the clayey soil baked hard enough to brake their implements, strained themselves to overcome every obstacle. A mournful silence reigned. Exhaustion was stamped on every face, but the hour of rest had not yet come, The pitiless eye of the manager patrolled the gangs and several foremen armed with long whips moved periodically between them, giving stinging blow to all who, worn out by fatigue, were compelled to take a rest. Men or women, young or old. "  Girard Chantrans 
(Voyage d'un Suisse en differentes colonies, Neufchatel,1785)

Not even the free blacks and mulattoes were exempt:

"It would be impossible to put too much distance between the two species, or to instill in the Negroes too much respect for their masters. This harsh discrimination even after manumission, is the principal line of subordination, because of the resulting idea that the Negroes color dooms him to servitude and that nothing can make him equal to his master."

A free man of color who struck a white man, whatever his stage in life, was to have his right arm cut off.

" These are dangerous people, more friendly to the slaves, to whom they are still attached, than to us who oppress them by the subordination which we demand and the scorn with which we treat them. In a revolution, in a moment of tension they would be the first to break the yoke which weighed on them, the more because they are richer and are now accustom to have white debtors, since when they no longer have sufficient respect for us."

The only privilege the whites allowed them was the privilege of lending white men money. Indeed, many of the mulattoes and the free blacks made fortunes in Saint Domingue, and became a powerful political voice  in the colony; but despite their economical force, the judicial system passed blatantly racist laws to oppress them .The west province even declared that the men of color would not be allowed to take the civic oath without adding to the general formula the promise of respect for the whites. They were forbidden to meet together "on the pretext" of weddings, feasts or dances, under penalty of a fine for the first offense, imprisonment for the next, and worst to follow. They were forbidden to stay in France. The clergy were forbidden to draw up any document for them. They were forbidden to take the title of Monsieur and Madame. If a white man ate at their house, they could not sit at the table with him. The white French planters were not the only racist ones in Saint Domingue; because of color prejudice the whites seemed always superior to the mulattoes and the blacks; and the lighter skinned superior to the blacks.       

From the underworld of two continents to Saint Domingue they went, Englishmen, Frenchmen and Spaniards, Maltese, Italians, Portuguese and Americans. For whatever a man's origin, record or character, here his white skin made him a person of quality; city vagabonds, fugitives from justice, escape galleys slaves, debtors unable to pay their bills, adventurers seeking adventure or quick fortunes, men of all crimes and all nationalities.