Some luxury hotels impose a standard service charge of 10% or 15%. In such places, I would tip only for something truly extraordinary.

One doesn't tip in Japan or in fact, in most of Asia.

Also, if you just get a map from the concierge or something similar, no tip is expected.

In the USA, some hotel concierges get kickbacks from restaurants etc. to which they send guests, although this shouldn't happen in a luxury property. IMO the tip should be adjusted accordingly.