This is another beautiful box from Tomoko Fuse's new book, Beautiful Origami Boxes. I'm not sure about the name of this box (the book is in Japanese), but the top looks like a star.
I folded it with A5 (210mm x 148mm) rectangles of copy paper, 2 for the lid and 2 for the base of the box. A5 size rectangles can be obtained by cutting in half A4 size papers, which is the normal copy paper size in many countries.
"A series" paper sizes are rectangles where the ratio of the longer side to the shorter one is √2.