According to German newspaper Bild-Zeitung "seller" demands 60.000 Swiss francs (48.000 euros) from newspapers where he offered his material.
Last week, Grenoble's hospitalal, where Schumacher was treated, submitted a law-suit for the stealing of his medical records.
Schumacher's spokeswoman, Ms Sabine Khem, is threatening with legal action, if any of the elements of the medical recorded be released, highlighting that the purchase of documents / data as well as their publication is illegal.
"For several days the stolen documents and items are for sale. The person behind this claims that the medical files belong to Michael Schumacher. We cannot judge whether the documents are original. However, the documents have clearly been stolen. The theft has been reported. The police have started investigations", she said.
"We advise that both purchase and publication of these personal documents are prohibited. The content of medical records is completely private and confidential and may not be made available to the public", added Ms Khem.
According to the information so far, the stealing act involves the two first pages of a 10-page file and a research is already conducted in order to ascertain the details of their removal.