score:11
1) You are travelling with one airline on a single booking: your luggage will be checked through to Tokyo. Aeroflot's information for transit passengers confirms that you do not need to collect your luggage in Moscow
2) You do not need a transit visa as you are transiting within the airport. From this site:
The following applicants do not require a transit visa:
Foreign nationals flying over the territory of the Russian Federation without changing flights in the country
Foreign nationals flying with an international airline and changing flights in the Russian Federation, at the same airport on both the outward journey and the inbound journey (on condition that this airport has a transit area), in possession of properly completed documents confirming their right to enter the destination country, and an airline ticket with a confirmed departure date from the airport in Russia where they changed flights, no more than 24 hours after their arrival date.
(bolding mine)
Upvote:3
Because your trip is in a single booking, you do not require a visa.
Per TIMATIC, the database that check-in staff use:
TWOV (Transit Without Visa): Passengers with a confirmed onward ticket for a flight to a third country within 24 hours. They must stay in the international transit area of the airport and have documents required for the next destination.
Upvote:6
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).