True.
The Berlin Decree issued by Napoleon on November 21, 1806, forbade the import of British goods into European countries allied with or dependent upon France, and installed the Continental System in Europe. It eventually led to economic ruin for France, while little happened to the economy of Britain, which had control of the Atlantic Ocean trade. Other European nations removed themselves from the Continental System, which led in part to the downfall of Napoleon.
The Milan decree, which stated that no European country was to trade with the United Kingdom, was issued the next year.