How about you hang some colorful prints on the portion of the walls going up the stairs. Or I would use it to hang a cuckoo clock. If it were me, I would use the portion under the stairs to make a small L-shaped library. I would also keep a small colorful rug for somebody to sit there and browse through the books.

I think there is absolutely nothing wrong with the space! The dark stairs are a beautiful contrast to the quartz wall and floor. I see a window just up the stairs...that will provide light enough!

I would add some small LED lights to the bottom of the upper pad there over that doorway, and some more at the top of a built in bookcase on the wall directly behind the staircase.... and put a few cushions on the floor under the stairs to browse and read; for showcasing a few books and other 'objects du art' (especially the top row of shelves under the LED's, to catch the light and sparkle) and turn it into a brighter space. In which case the dark stairs is a perfect counter. Tie in with a string of small framed art prints going down the wall at an angle OVER the railing on the wall with the switches and add a few more LED aimed lights over each one of the prints. (use small amounts of lighting to over all lighten the space)

I like the dark color too!

~Lyvonne

Thanks for your suggestions. There are already small LED lights (x5) in the left side of stairs. You can see the cables on the first picture.
I don't want to have bookcase directly behind or under the stairs, because I have extra rooms for books and also entertainment room (with billard and projector).
I prefer modern style and minimalism in my house. The walls will be white with an "acent" of gray coulour.
I made the worst choise, when I bought these stairs:(. I really dont't like them.

@Lyvonne...any lighting ideas here?
https://www.houzz.com/discussions/how-do-i-light-my-two-story-formal-living-room-dsvw-vd~756040

I also think the stairs look quite nice. It looks a bit stark now because it's empty all around it, but once you do the white/gray walls, it'll start looking better.

Consider playing up around that space with artwork that matches or complements your contemporary look. Check out my work for ideas. I have many originals, and hundreds of configurations of canvas prints that I can print to the size you choose. Also take commissions.

http://www.etsy.com/shop/katshoa

Enjoy decorating! The place will look great once everything is put in place.

I think the stairs look nice dark like that