There's a pretty great article here in English, full of details about this collection of over 30k amateur photographs: Catherine E. Clark, "'C’était Paris en 1970': Amateur Photography, Urbanism and Photographic History"

https://journals.openedition.org/etudesphotographiques/3407

Oh, and the source code for this website is here:

https://framagit.org/dohseven/paris-1970