Thanks for such positive comments!
It was painted with Tamiya's semi gloss black and the 2k clear (varnish) is made by Mobihel.
I smoothed the clear with P2000 and continued up to P10000. Then I used Tamiya's Fine and Finish polishing paste,
followed by Finisher's (ultra fine?) polish. At the end I gave it a wax treatment with Tamiya's wax - that's all.
I think that it's the 2k clear that takes all the credits for this kind of finish.