The seam looks okay. I don't even notice it on the first picture.

3 mm ??!!! That’s too much.

To me it doesn’t look right.

We recently installed Ceasarstone quartz and I’m happy how the installer made seams almost invisible. There is no height difference either.

Hi, it’s because the first photo is the good seam to the left of the cooker. The seam to the right is the one that is bad.

@sondramartina yours looks wonderful!

Your description sounds awful, but I can't see it in the photos. If it's really awful....contact the company owner. Get a redo.

Seams must be on plane to each other. Gorilla Grips are powerful enough to pull the bend out of a piece of engineered stone, so I don't know where they came up with this 3mm nonsense.

Estone seams not on plane after a year or so and these were nicely done:

There is a beautiful seam here; you just can't see it because it's on the bottom of the top. When pieces are cut perfectly square but installed out-of-plane, the bottom of the seamed edge can touch before the top. Nothing is strong enough to pull that together. That may be what happened to qb20, although it looks like they used factory adhesive match on one and clear on the other.

Thank you - so you are saying I should have someone come and fill in the seam? It seems like I have two issues, that it’s not level and that they didn’t fill it in, after only 2 days it is already full of crumbs and gunk (it’s just 2 inches to the right of the cooktop). We had a very bad experience with the installers so I don’t want them back. I tried to get another photo to show the difference in level (and you can see how dirty it already is). It’s surprising since the other seam is near perfect...

The right bad seam is level at the front edge but starts coming apart after a few inches and then stays pretty uneven all the way through. The left (near perfect seam) is not level at the bottom but pretty much perfect at the top (except for the back 3-4 inches which I don’t really care about).

"
Thank you - so you are saying I should have someone come and fill in the seam?"

That's one approach. Gouge it out, decontaminate, fill, scrape, call it good, and get a discount.

The alternative is a do-over which is more risky and no discount.

I realized that the standards are simply different in France compared to the US even though it is the same manufacturer (silestone). I was told that this is a good seam for France.

What does "a good seam for France" even mean???

I don't mind the color, but the change in level would be unacceptable to me in a new place. I'd get somebody to come and look and give you their thoughts.

Yikes! I’m from South Africa, a third world country, have built 4 of my own houses and helped with a number of other builds, all with Caesarstone counters in kitchens and bathrooms and NEVER seen seams that wide or uneven..... EVER. Get them to fix it. It’s not a cheap product and being engineered the differentials are almost negligible compared to natural stone, which is what I love about it. So their excuse is just that... an excuse for bad workmanship/installation. Sorry to hear about your bad experience.