On April 7 2018 Syrian 'rebels' claimed that the Syrian government had used chlorine gas and Sarin in an attack on the besieged Douma suburb near the Syrian capital Damascus. They published a series of videos which showed the dead bodies of mainly women and children.
Before the incident Jaish al-Islam, the main 'rebel' group in Douma, had already agreed to leave towards Idleb governorate. Under those circumstances the claims made no sense. The various details in the produced videos and pictures were inconsistent with a chemical incident.
The Organisation for the Prohibition of Chemical Weapons (OPCW) investigated the incident and in July 2018 produced an interim report (pdf) that showed that no Sarin was used in Douma. The OPCW inspectors had only found various chlorinated organic chemicals (COCs) which are common in every household. Media falsely claimed that those finds were proof of a chlorine gas attack.