Using Local History for Genealogical Research
Ancestors Among the French Nobility



It may seem odd, but some people chose to become French and when they did so, the process was termed naturalisation. One completed an application that was a demande de naturalisation, added much identifying and supporting documentation, and sent it off to the authorities. They would approve or disapprove the application and, if they did approve, send a certificate. We have come across others who requested from the authorities a certificate confirming that they had NOT taken French nationality.

The benefits of each usually had to do with one's children, especially if a father were the one becoming French or not as, for most of the nineteenth century, children born in France had the same nationality as their father. If he became French, they could inherit and have certain other advantages permitted nationals alone, such as serving in the army. Conversely, if he remained foreign, he might inherit from his non-French family, and his children were exempt from French conscription. One can imagine various scenarios where  one choice or the other would be more advantageous to a family.


The National Archives of France, les Archives nationales, have a jumbo-sized collection of the application files, or dossiers. The site in Pierrefitte has those dating from about 1803 (An XI in the Republican calendar) to 1930. The site at Fontainebleau has those dating from 1931 to 1988. The information in a file can range from just about nothing (especially in the requests for proof of non-naturalisation) to :

  • the full name
  • place of birth 
  • date of birth
  • address in France
  • family members
  • a copy the birth registrations, with translation, of the applicant, spouse and children
  • proofs as to financial solvency
  • documentation of service in another nation's military, if applicable
  • proof of employment
  • a letter from the town hall confirming place and length of residency
  • a letter from the prefecture supporting the application
  • a letter from the police confirming that the applicant had no criminal record

Quite a nice snapshot of a person and a family!

These files are absolutely crucial to any research on nineteenth century Jewish families in France and on the families of the refugees from the German annexation of Alsace-Lorraine. The former were often immigrants from other parts of Europe, while the latter, if they did not claim French nationality as Optants, would have had to apply to be "reintegrated".

The dossiers des naturalisations are not online, but much of the information from them is. 

  • For the years of 1814 to 26 May 1853, there is a database with the essential information extracted, called NAT. It includes files on name changes, titles and coats of arms during those years as well. Click on "recherche simple" to get a form in which to type a name. 
  • For the years 1855 to 1918, one can search the Bulletin de lois, in the ten-year indices. This will show only the successful applicants.

Within the two sites of the Archives nationales, there are of course, facilities for searching all of the years.

In Paris:

  • For the years from An XI to 1813, the dossiers are on microfilm
  • For the years 1814 to 1858, the same database, NAT, is available in-house
  • The years 1848 to 1883 are on microfilm
  • The years 1884 to 1930 are on microfilm and on the in-house database NATNUM
  • For those from Alsace-Lorraine and for foreigners who served in the French Army during the First World War, the years 1914 through 1923 are on microfilm

In Fontainebleau:

  • For the years 1931 to 1948, one must ask the staff for assistance
  • From 1948 onward, the case will have been mentioned in the Journal Officiel or will be in an alphabetical listing held at the archives.

In this way, some families that arrived in France from elsewhere can, if they chose to stay, be traced with some rather thrilling success.

©2011 Anne Morddel

French Genealogy