After demonstrations number 19 and 20 of the Yellow Vests, protesters claimed to have been hit more violently than with the tear gas usually used by the police. Its chemical compound has created controversy, some relaying on Twitter the results of medical tests that demonstrate cyanide poisoning.
A Yellow Vest member posted a copy of her medical test and a comment "positive cyanide tests" suggesting she was poisoned after having inhaled tear gas at demonstrations. French TV LCI first spoke to the protester and author of the Tweet as well as a toxicologist, who explained that the concentrations of thiocyanates found in the blood of this patient are compatible with concentrations observed in smokers and would have to be at least 10 times higher to indicate poisoning.
See further debunking by the LCI.