These conditions can ensure that the interests of Santo Domingo plantation owners will not suffer too much damage.
As for paying wages to the black workers, that part can temporarily be compensated by tax reductions from the Santo Domingo government. Once turmoil erupts in the Caribbean Sea, the price of sugarcane will inevitably skyrocket. The sugarcane plantations in Santo Domingo might even earn more than before, and that little bit of wage cost will be of no concern to anyone.
Of course, the British would not sit idly by and watch France make a fortune from Santo Domingo's sugar. Driven by the principle of "If I can't have it, no one will," they would definitely try to block the shipping lanes to Port-au-Prince.
Joseph had foreseen this situation and had thus prepared an "ultimate weapon" in advance.