That depends on the mood of the police force. Swastika (and Nazi salute) can be seen as an extremist symbol, so you may end up in jail. Still, in some city districts you can see a shitload of swastika graffities on the walls, a whole damn lot of juvenile boneheads strutting on the streets and occasionally beating the crap outta people they didn’t like for some reason, and nobody gives a damn about that.
Depicting Nazi symbolics for art/historical/reconstruction/entertainment purposes is legal, AFAIK, though it must not be used as propaganda.

I wonder, is publicly displaying the Nazi swastika illegal in Russia?

Main problem is that Russia proved to the world that “the Good old days” (soviet era), where russian word or signature dont mean shit, is back. Taking Crimea, how ever you call it, is a breech of Budapest Memorandum (look it up). Russia didin’t even try honor it . Obviosly Russian credibility will wall, nobody wants to do bussiness with people whose agreements and promises is just a faste of perfectly good oxygen. While Russia is a rich in raw materials,don’t forget that the Soviet Union didin’t survive isolation, nor wil Russia.Economy is more global than ever.

In longer run, don’t forget that Russia has a lot of disputed areas. If some day in future, some more powerfull country comes do help their oppressed brother in Russia,do you think the world will interven?No, ukrainians would but on their gasmasks, just do hide their grin.