At least 120 people were killed in different locations in Paris on Friday in a series of terror attacks.
French police officials advised citizens to stay indoors, and as the tragedy unfolded, Twitter user @RohanSinghKalsi put out this tweet.
#PorteOuverte, meaning "open door", is the hashtag being used on Twitter as a way to help people seeking shelter in the wake of the attacks.
Kalsi's tweet received immense support, being retweeted over 10,000 times in just a few hours.
But Kalsi himself refused to take any credit for it.
Follow BuzzFeed News' ongoing coverage in Paris here.