It was previously considered to be in the public domain because it is a scan (or similar) by the Bibliotheque Nationale de France, but not everything scanned by the BNF is automatically in the public domain.
It is possible that this file is in the public domain for other reasons, for example because it was published a long time ago (anything before ca. 1900 is most likely ok) or because its author / artist / photographer died over 70 years ago and it was published over 95 years ago. In such cases, a new rationale should be applied, and a different license tag (see Commons:Licensing and valid license tags at Commons:Copyright tags) should be used.
If the file is not found to be in the public domain, it might be nominated for deletion (NOT by any automatic process, but manually).
See below for the previous rationale (not applicable anymore).
Previous public domain rationale, no longer applicable
Public domain works must be out of copyright in both the country of origin and the United States, and must be accompanied one or more valid copyright tags to indicate its status. Absence of such tags may result in a file's deletion.
to share – to copy, distribute and transmit the work
to remix – to adapt the work
Under the following conditions:
attribution – You must give appropriate credit, provide a link to the license, and indicate if changes were made. You may do so in any reasonable manner, but not in any way that suggests the licensor endorses you or your use.
share alike – If you remix, transform, or build upon the material, you must distribute your contributions under the same or compatible license as the original.
