Here are the technical criteria for The Nordic Swan
And here are the criteria (Final draft) for the EU-Flower
But please notice that the EU-Flower is not officially approved, yet.
As you can read, ALL the elements of the book are considered, not just paper.
You must be aware that these criteria are not about the safety of the product/book (the safety is guaranteed by the laws). These criteria are something that you can voluntary apply for, in order to realize a greener product/book (using eco-friendly materials and using sustainable printing methods)