Diderot's "Encyclopedie" (completed in 1772) was an Enlightenment publication that offended the aristocracy as well as the Church. Diderot promoted freedom of religion, uncensored literary publication, and the importance of scientific reason.
Offending the Church
Some of his writing questioned specific facts within the Bible. He also stressed science over religion. Diderot offended the church so much with "Encyclopedie" and other publications that he was actually imprisoned temporarily in 1749! He also faced censorship of his writing.
Offending the Aristocracy and Government
Diderot wanted the French government to be more democratic and give the people more of a voice. This was a direct threat to the power of the aristocracy. He also accused the government of despotism and said that "the greatest good of the people is liberty."