Vertical or horizontal? Light cream if you want to allow light in when closed. Do you have to have access - waklking through them?

I didn't realize it was a faux stone pattern. There is nothing you can do to hide the grid pattern I am afraid...However, as it is recessed in a niche, I am inspired by your windchime pattern to think of adding eyelet hooks on the top and bottom that align with the vertical grids and uplight them from behind...This idea but with less vertical rods, and then uplit to give an effect like the second picture...

Hello Monika, I must say that concrete wall is fantastic! I see a large planter with a large leaved plant there.. I like Jonathan's idea, off white or shades of cream for the remaining walls and ceiling or even a subtle stone colour.. Then we need to talk textures! I think the sofa could work if you move it out a bit from the wall and layer it up with throws and add a couple of lovely cushions.. Warm woods would be nice too to balance the room.. Have you considered adding concrete to other areas of the home? There are some fantastic concrete chairs available both as a chair and bar stool.. Could be fabulous to compliment this room.. Cox and Cox did some pendant lights that were concrete with a warm edge detail.. You could create your own arrangement with a 5 wire ceiling rose and hooks.. A glass topped coffee table could be nice too.. Have a look at eBay or vintage shops.. Oh and one more thing... You can if you like the concrete wall find wallpaper for another room say that resembles what you have in the living room or even marble! It's fabulous and a feature you want to make the most out of! :))

I feel partitions are not needed. You already have too much for the space. Adding a partition will shrink the space further. The simplistic solution, you do not wish to discard any furniture would be to paint all the walls in lighter pastles. And use some wall painting frames to highlight certain walls.