During Friday's attacks in Paris, the hashtag #porteouverte, "open door", began trending as Parisians offered shelter to people stranded in the streets.  

Many users openly posted addresses on social media, while others offered to give their information to anyone who messaged them directly. 

In the midst of the attack, Parisians invited strangers into their homes.

Some offered places of worship as well.

The hastag was used in several languages. 

Some reminded others to stay safe at an uncertain time. 

Later a website was created with a map designed to help people get themselves to safety.