MEXICO CITY (AP) — Mexico’s president said Monday French auction houses had gone beyond the pale with brazen sales of pre-Hispanic artifacts.

President Andrés Manuel López Obrador said some auction houses had gone so far as to send Mexico’s archaeological institute photos of relics, asking if they were genuine, so they could sell them for more money.

López Obrador said he had issued orders for the government National Institute of Anthropology and History, known by its Spanish initials as the INAH, to stop responding to such requests.

“They, the organizations that auction these pieces off, are so brazen they ask the INAH for information, they send photos, so the INAH can tell them if these are authentic or fakes,” López Obrador said.

The president also took a dig at the French government, which has done nothing to stop a series of such auctions in recent years. López Obrador said the French should be more like the Italian government, which has made a point of identifying and returning ancient artifacts.

“It is very regrettable that the French government hasn’t passed legislation on this, as has been the case in Italy,” López Obrador said.

“We are going to raise this on the international level. We have managed to recover a lot of pieces and that is very important,” the president said. “For example, Italy and the United States have sent us a lot of pieces.”

He said First Lady Beatriz Gutiérrez Müller had written to France’s foreign minister asking for two upcoming sales of around 50 Mexican artifacts, including pottery and stone sculptures, to be stopped.

The Paris auction house Société Baecque et Associés is scheduled to auction off native artifacts from around the world on Feb. 9.

On Feb. 11, the Société Binoche et Giquello is scheduled to auction a variety of pre-Hispanic artifacts from across Latin America.

López Obrador said many of the pieces in those sales are fakes, and asked potential buyers “not to act like criminals.”

The president and the first lady have mounted a campaign to win the return of artifacts from the Maya, Aztec and other pre-Hispanic cultures, and the president said 6,000 relics have been returned to Mexico so far.

But despite letter-writing and diplomatic requests, Mexico has had little success in convincing the French to crack down on the lucrative trade.

The most recent occurred in November, when Christie’s Paris branch auctioned off 72 sculptures and figurines from the Maya and Olmec cultures despite Mexico’s claim that the pieces were national treasures and part of its national heritage. Fifteen other items failed to sell.

One stone Maya carving, traditionally known as an “Axe” because of its shape, went for almost $800,000 (692,000 euros). The Christie’s catalogue described the piece as a “sculpturally-carved with a bearded dignitary with his head dramatically thrown back and struggling with a sinuous, mythical rattle snake.”

Mexico previously failed to stop several auctions, including a sale of pre-Hispanic sculptures and other artifacts by Christie’s Paris earlier last year.

Mexcian archaeologist Leonardo López Luján, who has overseen the excavations in Mexico City’s Templo Mayor, wrote on his Twitter account at the time that “this is a never-ending story.”

“It’s proven that the old, recurring method of sending letters and demands does not have any effect, other than pretending that something is being done,” López Lujan wrote. “Complex problems are solved with complex strategies.”

Paris auction houses often sell Indigenous artifacts that are already on the art market, despite protests from activists who say they should be returned to their native lands. Christie’s said the Mayan sculpture, for example, had been bought by a European collector from the United States around 1970.

That appears to pre-date a 1972 Mexican law that forbids export or sale of archeological or significant cultural artifacts.