Wouldn't be my first choice -- would probably want a wider one -- but I do especially like the classic plain frame.

One thought: could you find a pair of narrow (rectangle or oval) framed mirrors that exact same height and that same kind of frame to hang on each side of it (with the tops of all even with the tops of the sconces)?

Suezbell thanks for you comments. Would you hang the mirrors outside of the fireplace area?
Like this?

Yes, IMO it is too small. To compensate you could put another piece of art above that one and make it work. The overall space needs to be taller and wider.

I prefer it be at least as wide as the firebox opening.

The center of the painting should be the same height as the center of the back plates for the sconces, or perhaps an inch higher than that. The painting will look a lot better once it is hung.

I would hang a large mirror ( nearly as wide as the outside tile dimension and about 8 inches higher than your art) with a thin frame just a couple inches above mantel. Lean painting, off center, against mirror. Usually looks best if painting is both on and off mirror but NOT evenly so.. Balance other side only if you want to.

Thanks for all the advice. I have more art pieces but this is the one where the colors work the best with the tiles around the fireplace.

Yes to what hollybar said, my thoughts too if you like that painting.

I think if you hang it as Lars describes and use some things on the mantel to balance it (nothing too small or symmetrical, as the sconces are already symmetrical), it could work.

It is a lovely piece and your fireplace is gorgeous!!

following

Find a piece in your collection that is the right size and please not just because it “goes” with the room IMO art above FP is usually already to high and hanging it higher won’t help. Don’t hang mirrors unless they are reflecting something worth seeing twice and that is not the back of a piece of art Maybe do something like this

You have a unique place. Yes, the art is too small for there. I would not add mirrors on either side. There are too many hard objects on either side of the fireplace. You need some softening. I'd use those pieces elsewhere and add a lamps or a lamp and a tree.

I agree with Lars and Oly. You love it there, so hang it up and add some symmetry with decor on the mantel, and THEN decide. It may not be the perfect size, but it could look nice once hung and be perfectly acceptable.

I think the size closes the space in where a larger size expands the space. Depends on which look you like.

If you add a pair of mirrors or other rectangle art or decorations of any kind -- even candle holders or oil lamps, etc., on the mantel -- to create a wider visual, keep them close enough to the art so they set above the metal firebox surround.

If you replace the art or if you REFRAME the art you have (with an additional mat or even "framing" the framed art) so the visual will be wider, the width of that metal surround is how wide you'd want it to be.

If you have documentation about the origin of the art or a picture of the artist that is frame worthy, even that could be framed beside your already framed art in a wider frame, perhaps in a recessed/protruding way.

https://www.chelseaframes.com/framing-stories/

You could hang your framed picture off center and add a totally different kind of art beside what you have -- as long as it "relevant" (in your opinion) -- such as a pressed metal bird common at the beach could be hung by a beach picture.

Yes, sometimes art works "talk" to each other. Maybe another work, leaned against the edge of it would create that conversation.

The most important thing is you like it!! Hang it where you want, I think it will look fine & make you smile when you see it.

When you're through considering all your options, eandhl2 is right:

"The most important thing is you like it!! Hang it where you want "

Idea for your corners:

https://cornerbookcases.files.wordpress.com/2012/09/corner-bookcase-14.jpg

and you can still put any furnishings you want in front of them.

Thank you all!! There is another art piece that is a bigger and might work there. I will use that other one or change de frame and mat (to bigger ones) on this one. From all of your opinions it was clear to me that it does look small. :)