First of all go see some accountant and found out exactly how much tax you would owe, you might be surprised it might not be that much. Especially if your work income is also low. Some countries have different rates for capital gains than others.
I don't think its worth it to move to another country, live there, get a citizenship, just to cash out crypto tax free. What about your friends and family back home? And if you come back, France will ask where you got this money from, what will you say then?
After you add up all the expenses and headaches you will realise you are better off just paying the taxes in your country and moving on with life instead of complicating things.