In the wake of the horrific terrorist attacks in Paris on Friday, people around the world have been showing their solidarity with France.

Some have taken to Facebook to give their profile pictures a blue, white and red filter. Iconic buildings around the world - from the Empire State Building to the arch of Wembley Stadium - have also been lit up in the tricolour. 

But perhaps what's capturing the French spirit the most is a two-minute clip from the 1942 World War II film Casablanca, which has been shared thousands of times on social media over the weekend.

In the scene, Victor Laszlo, a leader of the Czech Resistance (played by Paul Henreid), sees a group of Nazi soldiers singing their patriotic anthem "Die Wacht am Rhein" in a bar in Morocco.

He then leads the band and customers - many of whom are French - to sing an impromptu rendition of the French national anthem, La Marseillaise, to quieten the group of Nazis.

The scene ends with the crowd crying out "Vive La France!" in unison, which means "long live France".

"What a perfect scene at the perfect time. I have many friends who live in Paris, and they are so upset and completely frightened. I just love when film captures the spirit of a nation. Whether or not it is politically relevant is immaterial, all that matters is that there is a sense of solidarity." wrote one user on Reddit after the clip was posted in the early hours on Saturday. 

"I have probably seen Casablanca 20-30 times, and this scene still gives me goosebumps every single time. Watching it in the context of this morning, it brought tears to my eyes," said another.

Politicians, actors and notable personalities shared the clip on Twitter, including Stephen Fry, French actress Michèle Laroque and Fahrenheit 9/11 filmaker Michael Moore:

Casablanca was made during the Second World War and the Nazi occupation of France. 

It is thought a number of the extras in the scene were refugees from Germany and that their tears while singing La Marseillaise were genuine.