BE CAREFUL ! Répertoire des Sociétés et des Indépendants is not RSI.
Maybe you received a letter from Répertoires des Sociétés et des Indépendants RSI with a logo which looks like logo's RSI (Régime Social des Indépendants). This letter is charged with a bill. Don't pay it ! It's only a trap to catch your money without any return.
If you have any doubt, don't hesitate to call your adviser.