Here is a few things i have found
Image of the back of the booster pack you linked which i translated with google translate
Image of part 1,2,3 Booster packs
Ebay listings which match what is on the front of the packs which may be what is inside
Looks like its some stickers and a book from the images, Google translate of the pack states 2 sticker sheets & 2 books if that is correct
Hope this helps 