I suspect this designer purchased a second-hand table, cut it in half, painted it, and mounted it to the wall before adding a marble top and sink. There are very few millwork shops in this country that have skilled craftsmen that can still produce this type of furniture. Most of the carved pieces are fabricated overseas and for large volumes. You're a designer.....think outside the box.

The problem with purchasing a demilune table as I show below is getting one deep enough to accommodate the depth of the sink and faucets.

All of these traditional vanities were listed on Home Depot. If you're willing to take a vanity where the plumbing is concealed, you can have these refinished to the color of your choice or even have a new design for the marble top.

I agree probably a table cut to fit but there are lots of vintage type tables you coulld have modified. Maybe give us some idea of the project .To have this built to match will not be cheap

I am thinking the OP means the sink and counter not the cabinet since it's sooo obvious this is just a remade old table.

Thanks everyone. According to the designer, it's custom! I found one place that is close, J. Tribble