France defies the Islamists

Rico says he wasn't the only one who thought of the movie, too, apparently, as Alice Vincent has an article in The Telegraph about the same thing:

As the world reels from the horrific events of the terrorist attack in Paris, France, people have started to share a clip from Casablanca to show their support for the people of France.
A two-minute YouTube video (below) of the scene from the 1942 film, in which character Victor Laszlo (played by Paul Henreid) leads customers of a bar in singing an impromptu rendition of the French national anthem, La Marseillaise, to silence a group of Nazis who are singing Die Wacht am Rhine.
The scene ends triumphantly, with a young woman crying out Vive La France!, a statement that has been adopted across the globe in the aftermath of the attacks. The scene is famous within cinematic history, mainly because Casablanca was made during the Second World War and the Nazi occupation of France.
It is said that the tears seen in the eyes of the extras singing La Marseillaise were genuine, as a number of them were refugees from Nazi persecution in Germany.
Humphrey Bogart, who played Rick Blaine in the film, the owner of the cafe in the scene, was called into the studio to stand in the middle of Rick's Cafe and nod, but was apparently unaware of the significance of his character's approval: that he was giving the okay for the band to play the song.
The video has been shared hundreds of times by people including German MP Omid Nouripor, comedians Michèle Laroque and Patton Oswalt, and US documentary makers Nev Schulman and Michael Moore. (And, of course, Rico.)