Lawyers representing survivors of a chemical weapons attack in Syria in 2013 filed a criminal complaint against the Syrian officials they blame for the deaths of hundreds of civilians in a rebel-held area. France is home to thousands of Syrian refugees and investigating judges have a mandate to determine whether crimes against humanity were committed anywhere in the world. The case, which about a dozen people joined, comes after a similar one was opened in Germany last year. It offers a rare legal avenue for action against the government of President Bashar Al Assad. Attempts by western powers to set up an international tribunal for Syria have been blocked by Russia and China at the UN Security Council. "This is important so that the victims have the possibility to see those responsible being brought to justice and held accountable," Mazen Darwish, who leads the Syrian Centre for Media and Freedom of Expression in Paris told Reuters. The group filed the complaint along with two other NGOs – the Open Society Foundation's Justice Initiative and Syrian Archive. French intelligence services concluded in 2013 that a sarin gas attack that killed 1,400 people in the Eastern Ghouta region, south-east of Damascus, that killed 1,400 people was carried out by Syrian government forces. The government denies it used chemical weapons against its civilians. The complaint is based on what the lawyers said was the most comprehensive body of evidence on the use of substances such as sarin gas in Syria. It includes evidence from survivors and defectors, an analysis of the Syrian military chain of command and hundreds of items of documentary evidence, including photos and videos. "We have compiled extensive evidence establishing exactly who is responsible for these attacks on Douma and Eastern Ghouta, whose horrific effects continue to impact survivors," said Hadi Al Khatib, founder and director of Syrian Archive. In 2016, a UN-commissioned investigation to identify those behind chemical weapons attacks in Syria found that government forces used chlorine and sarin. Mr Darwish said he expected another case to be opened in Sweden in the near future.