This study aims at exploring some statistical aspects in response to the increase of foreigners and immigrants within the population of Korea. Such an interest conducts our case study of France with regard to the census and legal systems that restrict definition and measures of foreign population in the country. This study also explores historical background, legal entities and authorities involved in policy-related decision making in census and other statistics, and processes of statistical production on the concerned population. Also, an importance of statistical contributions to the immigration policies is discussed.