In 1789, Martinique slaves revolted partly because of the influence of the new phase of the French Revolution. The instability of Saint Domingue also increased. On 17th June 1789, the Third Estate declared itself the National Assembly in France. And on 14th July 1789, the fall of the Bastille triggered the commencement of the French Revolution.
The short answer being the new phase of the French Revolution because the armed popular masses, on which the revolutionary rested, were in favor of the abolition of slavery. Hope this helps!