Who was affected by the Embargo Act of 1807?
The American people not the targeted nations of France and England.
The French and British were abusing American shipping during their wars against each other. The British were stopping American shipping and impressing American sailors and forcing the Americans that they claimed were British deserters to serve on the British warships. The French were stopping American shipping and taking the goods claiming that the goods were contraband intended to help England.
France and England depended on American cotton, lumber , tobacco, and sugar. President Jefferson felt that the embargo that prevented the exportation of American goods would force the warring nations to respect American neutrality.
France and England could still import goods to America and ignored the embargo and continued to abuse American shipping.
The people that were affected by the embargo were the America people. The loss of income due to the embargo hurt the American people.