• The development of the code fundamentally changed the nature of the civil law legal system. It stressed clearly written and accessibly law.
• The laws could be applied only if they had been promulgated and then published officially. No secret laws were authorised.
• It prohibited laws that apply to events that happened before their introduction.
• The codes also prevented judges from refusing justice based on insufficiency of the law, meaning they had to interpret the law.
• It forbid judges from passing general judgments of a legislative value.

The Code was adopted in many countries occupied by the French during the Napoleonic Wars and became the foundation of the law systems of Italy, the Netherlands, Belgium, Spain, Portugal and their former colonies, and Poland.

Romania also used a civic code with strong Napoleonic influences until 2011. Thus, the civil law systems of the countries of modern continental Europe have been influenced by the Napoleonic Code (except for Russia and the Scandinavian countries).