I already done the transit in Moscow without visa, so I can confirm there is no problem, and you are using long leg flights (and possibly large airplanes), so you should also not get problem with transit.
You can check your booking on Aeroflot website (it is also in English, not sure about French). Check in which airport and terminal are you arriving and departing. Then check the transit instruction in https://www.aeroflot.ru/ru-en/information/airport/transit
You should be careful on airport: sometime there is a small corridors for international transit (most people will go straight to immigration): so before going to police control, check that you are really doing a transit (the deviation is in the same room, on some side, of just before entering in the immigration room).
Sometime it is impossible to do the transit without transit visa, but this usually imply short haul flights (e.g. to small airport on ex soviet countries) and changing air carrier, which is not your case.
So to be 100% sure: go to Aeroflot website, check your booking for the airport and terminal: then the above link will confirm you that there is a transit (so visa free).