I'm not sure tiara is the correct word for this braid, but I couldn't think of anything else.
I think this braid is so great because you can sleep with it and then it looks even better the next day. And since I've grown out my bangs I love to keep my hair away from my face like this. It's super simple to make but I thought I could make a tiny tutorial and explain anyhow.
Wash your hair and make the braid while it's still a little moist. This helps especially if you have fine "slippery" hair. Might not be necessary if you have dry colored hair. Divide the front hair that you want to have in the braid (and add hair behind the ear) and put the rest of your hair in a bun so it's out of the way.
Start behind one ear and make a dutch braid (like a french braid but inside out). Keep your hands strong and make the braid tight. Finish it behind the other ear, close to the neck. If you finish just before the ear it will look bad. Either braid it a little further down or strap it with a thin elastic band just behind the ear.
Let the rest of your hair dry and then curl the upper part of your hair. I have very thick hair so it takes ages to curl all of it. But I usually just curl the the top hair and then comb it out so that the hair feels more flowy. I don't use any products for this. If I curl my hair directly after I've washed it, it stays flowy for two days. I usually like this hairdo best after I've slept with it one night. Then the braid isn't so strict and the curls are much calmer.
If you have natural curls you're lucky and you can skip this last part :)