Siberian overflight fees

[Cyrano]

I understand that airlines flying over Siberia en route between Europe and Asia have to pay overflight charges, which end up subsidising Aeroflot.

This has been a long-running bone of contention between Russia and the EU:
Overflight fees bring EU lawsuits (https://themoscowtimes.com/articles/overflight-fees-bring-eu-lawsuits-4565) (from Moscow Times in 2011)
EU, Russia resume talks on Siberian overflight fees (http://aviationweek.com/awin-featured-story/eu-russia-resume-talks-siberian-overflight-fees) (from Aviation Week in 2013).

The latter article says
European airlines currently pay €300-400 million ($390-$515 million) a year for the right to fly over Siberia, according to the EC

Can anyone point me to any information on how these specific Siberian overflight charges are calculated? Do they vary by nationality of carrier, or by aircraft type, or by routing?

Thanks in advance!
C.

[Heathrow Harry]

Those articles are quite old see current situation at
International aviation: Russia - Transport (http://ec.europa.eu/transport/modes/air/international_aviation/country_index/russia_en.htm)

Write to the Russian authrities saying you're planning an airline operation Shannon- HK - I'm sure they'll tell you