Madelin is the best. No one ever knew more about the period than he did. He wrote his 16 volumes at the end of his life, when he had not only great knowledge but also deep understanding. There are plenty of the 16 volume sets around. The going rate in Brussels is 175- 200 €
He was the assistant of Houssaye but never got a university chair himself because of his work about Fouché which was considered as a rehabilitation of the mitrailleur de Lyon by the academi (-cs) (-ciens) like the all powerful Labrousse. The quality of the research is academic, the writing style is very accesible.