I don't think that he made alot of money from Decale Gwada. Last year, I watched a documentary about Dadju's life on the French television, him saying that people were surpised to see him (still) working at that Mac Donalds, while he had his first hit on the music-scene that was hitting the top of all music-charts in France.
When my nephew would watch Jessy's videos he used to make on youtube and dailymotion with La Selesao being on tour or normal videos, etc. It seems that he had just a normal life while French popstar that have money, always tend to show off on their socials and often migrate to the US, Belgium or Morroco when they are millionaires. The difference just being that he was the first one of his generation that was signed to mayor label, having to chance to tour here and there and get heavy promotion in the French television when releasing his singles and albums. At the same time, some were not being happy with the music that he was making saying that it was too mainstream from the music used to make before signing with a mayor and prefering Anges d'Afrik, Bana C4 and others that didn't sign with a mayor yet.