I am french and US american but have been living in France since the seventies. I have never filed taxes in the US but have filled in FATCA forms. I am not taxable for the US. However, sometime soon I wish to sell an apartment I inherited that is worth around 400,000 euros. I have not yet renounced

Should I do so before selling the apartment? or, will they not necessarily find out and then if FATCA is removed, I will not have had to renounce the citizenship. Thank you very much.