Answer:
It is a reliable source insofar as it is a comprehensive legal document that was revolutionary at the time, that was adopted in most of Europe, the Middle East, and Latin America, and that described many situations and behaviours present in Frnace in 1804.
However, as a legal code, its main goal is not to describe life in France at the time, and for this reason, its reading should be complemented with other books in order to better comprehend life in France at the time.