For those interested in the origins of the Daguerreotype, the Paris photography school Speos and the museum Maison Nicéphore Niépce in Saint-Loup-de-Varennes have launched an online publication of Niépce – Letters and Documents, a collation of the correspondance of Nicéphore Niépce (1765-1833).
The revised online edition of Niépce, Letters and Documents is a compilation of over 700 documents from more than 50 international archives. Some brushing up on your French required.