Dear Mr. Wong,
The contents accessible on Gallica website are mostly digital reproductions of works from the collections of the BnF that are no more protected by intellectual property rights. They can be downloaded and printed by clicking on "Download / Print" on top of the documents and also be inserted on a website through the "Embeddable widget" at the botton of the documents.
You may use these documents from Gallica according to the "Conditions for the use of Gallica's contents" available on Gallica website : <http://gallica.bnf.fr/html/conditions-u ... s-contents>.
Département de recherche bibliographique
Bibliothèque nationale de France