In the local French Creole language, it is called 「Fèt kaf」, the ‘black people festival’. The reason behind this obviously rough title, is that on the 20th of December of 1848, an announcement that came from mainland France to French colony Réunion Island – anciently known as île Bourbon – was eventually enforced by the locally famous colonial administrator Joseph Sarda Garriga. This announcement was putting an end to slavery in all French colonies for good. Local owners had never been willingly agreeing the French Republic’s project of abolishing slavery. It was officially banned during the 1789 revolution though, but most people tend to forget that Napoléon Bonaparte was the one who allowed colonial fields owners to buy and use slaves again. This is why we had to wait until 1848 to witness the complete end of slavery in French colonies.
The Fèt kaf which commemorates the abolition in Réunion Island, is held on the 20th of December each year. Celebrations include musical shows in the biggest cities of the island, during which the old slaves style music maloya  is played among other styles ranging from traditional music to modern rock and reggae.
Having been raised for a big part of my childhood on the island and having myself ancestors who have been directly or indirectly responsible for enslaving people during previous centuries, I take it as a duty to always remember and commemorate myself this day every year, wherever I am.
I wish you all a happy Fèt kaf. May human beings never suffer again the unfair treatment that our ancestors have been responsible for, during more than a century.
 Here is an example of this type of music: 20 désanm by Lo Rwa Kaf (https://open.spotify.com/track/1v5gxZKJ9LITPz27bGlcx2)