Tax after the sale of imported pictures as KC

[vg_edger]

Natural person has imported picture , purchased at auction in London for 1 million rubles. The film was declared on form TD -6 as KC. Accordingly, no duty on imports not paid. A month later, the owner sold it to a picture of an antique store in Moscow for 2 million. What tax thus should be paid ? For what amount? Since the total amount of sale or on the difference between the buying and selling?