Immigrations resulting from decolonization challenge the ability of researchers to track accurately the incorporation of the second generation through classifications based on country of origin. This article considers a classic example of such an immigration - from North Africa to France at the time of and after the independence of Algeria, Morocco, and Tunisia. This immigration was ethnically complex, composed - to take a rough cut - of the former colonists of European background (the pieds noirs) and low-wage laborers belonging to the indigenous population (the Maghrebins). A historical review indicates that the key to distinguishing these two groups lies in the exact citizenship status of the immigrants, for the former colonists were French by birth and the others generally were not. Analyzing micro-level data from the censuses of 1968, 1975, 1982, and 1990, we apply this distinction to the family origins of the second generation, born in France in the period 1958–1990. We show that the pied-noir population exhibits signs of rapid integration with the native French, while the Maghrebin population remains apart. A logistic regression analysis reveals that, based on a few characteristics of their parents, one can distinguish the Maghrebin from the pied-noir second generations with a high degree of accuracy. This finding demonstrates the sharp social distinction between the two groups and suggests a method for future research on their incorporation.