Why would Voltaire be considered a French philosophe?

Denis Diderot, a frenchman, planned to publish in a set of books all the new knowledge discovering the Age of Reason. Diderot said his goal was nothing less than "To assemble the knowledge scattered over the face of the earth, and to transmit it to those who come after us" Beginning in the 1740's, Diderot spent thirty years working on his encyclopedia meant a course of general education. More than two hundred important enlightened thinkers, such as Rousseau and Voltaire, wrote articles for the encyclopedia. The encyclopedia was not just a collection of articles exploring new areas of learning. The encyclopedia called into questions the teachings of authorities in every field of learning. He made it because he wanted people to learn from it.