Translation:He learns French instead of Russian.
Should "la rusa" take the -n accusative ending after the preposition?
If not, what's the difference between this sentence and "Mia avino ĉiam trinkas teon anstataŭ kafo" (where kafo doesn't have the accusative marker after "anstataŭ"). Dankon!
Really? I would have considered it a direct object as well, given that it's learning French instead of (learning) Russian, i.e. Russian could be seen as another object of the verb "lernas".
At any rate, there certainly is an inconsistency between this one and the one OP gave as an example.