Refuge is being offered to people stranded near Munich through social media.
Several people are feared dead and many are thought to have been injured in a gun attack near the Olympia shopping centre, prompting the closure of transport links across the city. Munich Police have urged people to avoid public places.
In response, hundreds of people have taken to Twitter using the hashtag #OffeneTur - or #OpenDoor - inviting people to stay if they are unable to get home.
Facebook's Safety Check feature has also been activated so that people can let friends and family know that they are safe.
It was most recently used in the wake of the Nice attack earlier in this month.
People also opened their homes under the hashtag #PorteOuverte during the Nice attack and Paris attacks in November to help people find safety.