The 13th Amendment 1865 did not end all the miseries of the African Americans. Their freedom was limited-politically, socially and economically.
Social limitations : They were forbidden to serve in juries, testify against whites and serve in state militias.
Economic limitations : They mostly worked as tenets and under Black Codes they were forced to sign an annual labor contract with white land owners and and upon refusal they were arrested.
Political limitation : The African American even after 1865 did not enjoy a full citizenship rights. An African American could be charged of anything and thrown in prison for vagrancy and then never be heard of again.
Poles have been allies of napoleon large polish community settled in france in the 19th century and poles and french were also allies during the interwar period.