I fail to understand your reasoning, France is less liberal than USA the state is rather strong and they directly tax most salaries upfront of it being paid each month, they know all your property in France as these are all registered. Generally they monitor your bank account via the bank themselves that are controlled a lot so they know your income and taxes are prefilled in France. Since most of my income is my salary I have basically never filled taxes I just verify and click accept each year. So yeah it is not difficult for them to implement such programs and it a much more easy and factual data to collect than ‘is this person a minority’