France’s National Assembly library acquired the Codex Borbonicus in an 1826 auction, according to the institution.
However, the codex is believed to have been stolen from a library in Spain years earlier during the Napoleonic era.
The Codex Azcatitlan was donated to the National Library in 1898 by Augustine Goupil, widow of the Franco-Mexican collector Eugene Goupil, along with other manuscripts, Jacquot said.
Both texts depict the Aztecs’ migration to Tenochtitlan (or, present day Mexico City).

French president Emmanuel Macron and Mexican President Claudia Sheinbaum
The manuscript dates from around 1519, just after the Spanish touched down in Mexico. Composed of pictograms, the Azcatitlán’s 25 folios feature a succession of Aztec rulers, and dramatize the arrival of Hernán Cortés and Christianity.
They were gifted on the condition that the collection “always be preserved in its entirety in the Library”, said Marie de Laubier, the National Library’s collections director.
The swap is historically auspicious because the codices are rarely on public view, and rarely travel. It’s particularly meaningful on Mexico’s end, given the country’s long quest to repatriate Mesoamerican cultural objects that have “found” their way into collections across the pond.
Ball’s in your court, Europe. As Emilia Mendoza, a Mexican restitution activist, told The Art Newspaper: “The loan is a good signal, but we want something permanent.”
-.-
Another way of restitution

The Museum of Looted Antiquities (MOLA) mentions a fully different way of restitution in 1982. It is about the Aztec codex The Aubin Tonalamatl. In June 1982, a 36-year-old Mexican attorney and journalist named José Luis Castañeda del Valle stole the Aubin Tonalamatl, stole it in broad daylight from the Bibliotheque Nationale in Paris.
France notified Mexican authorities of the theft but Mexico refused to return it, claiming it had vital status as Nahuatl cultural patrimony and was of national importance. In 2009, Mexico and France agreed for the codex to be on permanent loan to Mexico, requiring renewal every three years.
