SFGate

All About Interiors LLC Hi
First, you would want to paint the panel box the same color as the wall so it blends in, not sticks out. Second, is that light a necessity there? It is kind of awkward. If it must stay, then I would just put some accessories on the table that are at a higher height. If the light can go, then you can place a large mirror above the table to blance it out. I hope this helps. Good luck!

Krishna Equytech I am agreed with All About Interiors LLC, but if you want crazy look on wall then go for Lamp Shade Decals according your wall color

More Than Murals I would move the light fixture either higher or remove. If the panel is something that is accessed frequently you could frame it out & put a mirror or art in it, then complete the wall will several other framed mirrors or art/photos, instead of one single item.

tichitadias Unfortunately i can't paint the walls (it's a rental appartement, i don't own it). So, i need ideas to cover up...
For the light : yes, i need some kind of light here but maybe changing the lamp would help!

rinqreation A nice big poster or mirror (to cover up this wall's blemishes) and a 'better' uplighter?

tichitadias Thank you for your replies. I will see if it's possible to move the light fixture...

carole i would wallpaper and hang different size mirrors and/or pictureframes together and change the lamp
that way the things that are already on that wall will "dissapear" in the mix...

njmomma I would get a very large vase and fill it with your favorite color flowers. That should cover the box. Change out the light fixture and add a mirror to the wall. Some low accessories, a dish to catch keys, wallets.

njmomma Some pics.