I think an ochre colour would allow your paintings to stand out whereas they would be lost on a dark green background. Many years ago I used Crown paint called Tapestry Thread which was a lovely ochre shade and I think from their Period Colours range. It may still be available from a Crown Decorators Centre.

I love stronger colours and I like both.

Since most of your Artwork are with cream colour paspartouts and gold frames and I pressume you would like to keep some of them, I would not opt for the ochre colour walls, because your room would be too much tone in tone. I can imagine it with that green tone, less Artwork with more spaces between the paintings and perhaps paint the white TV stand in the same colour. Cool option - put some small bits of colour matching wallpaper in the back of your TV stand! Just an idea to pep up your furniture piece in case you are keeping it.

Maybe a more deep yellowish green so it has both tones?

Green so the pictures pop

How much light does that space get? Paint samples on the walls and see how they reflect the light. While dark paint does make a space more cozy it can be modified by using a lot of brightly colored furniture and rugs as a counterpoint. At the moment, green is really the color. If you get a lot of warm sunlight in that area, the mustard could look really brassy and harsh. Either way, whatever color you choose you’ll need to counterbalance it so that it’s not overbearing. The green can be counterbalanced with golds and the mustard can be counterbalanced with bits of blue or grey.

Second comment now that I’ve looked more closely at your photo. You sofa has a bit of a pinkish blue tone to it, although it is beige. I would not like that next to the mustard. Furthermore, your floor is quite warm and that next to a cold mustard may not look good. You will need to do large color swatches on your wall and you’ll see what looks best.

Green. Definitely green. That will also help to swallow up the black TV, which would stand out horribly against mustard. Also, your ceiling light fitting with mustard.. . . no.

Agree green