As the French government has stated,
there is absolutely no proof for this claim.
Rather, the poster posted the Tweet to disrupt information flows and obscure the truth.
Curing disease is not a side effects of taking cocaine. Its impact is most widely linked to risk of death; violent behaviour; increased heart rate and blood pressure; dilated pupils; extraordinarily high blood pressure and constricted blood vessels.
Moreover, there is currently no cure for COVID-19.