I think we are maybe not being very clear about what constitutes "earnings". If we are talking about turnover, then in a micro BIC 50% of it is written off for material cost (and that's usually about accurate) and then 24.6% is your cotisation charge of what's left. So overall, yes, you only keep about 25% of what you take.
But if we are assuming that we are only talking about the "imposable" amount to start with, then about half of it will go in cotisations so if Celestine has been putting aside 40% then she only has a small shortfall to make up.
Lisa
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