Shortly before midday on Monday Bild published a short article with the headline “several injured after tear gas attack!”

In the article Bild explained that the attack had taken place at Frankfurt Airport and referred to a tweet from a Max Schneider as their sole form of evidence for the alleged attack. But a strange evidence loop emerged as Max Schneider's tweet referred to Bild as his source of information.

The news soon filtered through German online media and Twitter before being put up by international media outlets including the Daily Mail and China Xinhua News.

The reality of the incident is somewhat less dramatic. The fire services were called in after some passengers complained about breathing problems. But after they could not detect any form of gas in the air they gave the all clear.

Check-in counters which were temporarily closed were reopened by 12.30pm.

Federal police say that six people are being treated for “light injuries” relating to their airways. The source of the passengers’ breathing problems remains unclear.