This is a Massimo Dutti fine cotton shirt - size EUR 38 - would easily fit size 8/10 and 12 too. It's very light, fine and quite floaty.
It has concealed buttons down the front. It looks rather creased in the photograph but that is just the quantity of fabric - it's fine to wear.
As is my usual annoying habit, I cut the fabric information off because you could see the label through the fabric but I'm pretty sure it's a very fine cotton and I wouldn't hesitate to wash it and hang it up to dry which it would do very quickly.