I’m not the biggest fan of those two tile combinations, but a less brown wall color might help the room blend better.

So it was placed to reinforce the circular shape of the foyer. It's too warm compared to your tile. Can you get more of your tile and just replace this?

You can replace the circle with the same tile turned on the diagonal

You can replace this with a contrasting colored tile.

Here are inlay options.

It's not you - the walls work well with the tile but the circular area is definitely much warmer in tone. I think Beverly's idea of simply replacing with existing tile is best. You can always add a fun rug to coordinate to your current taste but a medallion can look dated after a time as other elements in your space change. Looking at your wall art and fireplace, if you go the medallion route, it should be understated and not fancy or fussy.

The beachy tile accent would drive me crazy too. Is the square floor tile available, or, perhaps, there’s some leftover. But I do like your smiling bear.

Apply a enhancer to the stone. It will completely change the overall appearance. Whether it's for the better is up to you. Not a designer and I don't play one on Houzz. Quick easy and inexpensive way to try an alternative before spending $$$.

Example - Same stone. Shower floor is a penetrating sealer. Mock up sample is a enhancer.

The walls are reinforcing the brown in the mosaic. If you tone down the brown in the walls you will tone down the colour in the flooring. I like the inlay. It gives the foyer a reason for being in that configuration. And the brick fireplace that is poking out of in pic #3 is IDENTICAL in colour to the inlay.

To me, the square tiles are the aberration not the mosaic.

Try an enhanced seal as above............and be prepared to rip it even then. When you mop.......does it look much darker/better for a minute or two? That's what you will get with an enhanced seal.

The only thing that would make this look right is a border...

Nothing will make it "right" . Big deal......a circular entry. The walls defined it! and EVEN if you do something to call attention to the floor? That is too large and not well done. It's an example of why we say:

Design is editing.......: ) As in do you NEED it? Maybe not lol

You need "grandeur" To pull off grandeur. That most resembles the shower floor in a lake house. I'd have my sledge out soon.. I can say it would drive me nuts.

Jan is right...bottom line “you hate the tile”...do you want to make it look a little better with least amount of effort?...if not ...can you ...or do you want to ....match the surrounding tile perfectly?...the bottom line it is a poorly executed version of a very elegant concept..are there other acceptable ways to change it to a more “open foyer concept”?...can some of the columns be removed?

To me, the square tiles are the aberration not the mosaic.

I agree.