Ms. Diallo’s documentary “From Paris to Ferguson: Guilty of Being Black” (“Not Yo Mama’s Movement” in the United States) examines the pervasiveness of ethnic profiling in abusive police identity checks. She has also addressed a recent death and a brutal beating of black youths by police officers that led to a Black Lives Matter movement in France. She has called all this evidence of institutional racism. That view has led the right wing, and some on the left, to successfully pressure the government of President Emmanuel Macron to oust her from a government advisory council, exposing a hypocrisy at the heart of French nationalism.