The French government bans the use of hydroxychloroquine in the treatment of patients with Covid-19, the disease caused by the coronavirus.
Researchers have warned that using the drug could potentially be dangerous.
Hydroxychloroquine, which is used, among other things, to treat malaria, is prescribed in some places in the world for corona patients.
Doctors are forced to resort to such drugs because there is not yet a drug specifically developed to treat Covid-19.
The best-known user of hydroxychloroquine is believed to be US President Donald Trump.
He previously stated that he would take the drug as a precaution during the corona crisis, although he would have stopped doing so in the meantime.