"Savage", this is what an American on YT said of the Marseillaise lyrics, reading their translation. And well... he's perfectly right. France national anthem is savage. "let an impure blood water our fields", the "impure blood" being that of the enemies of France whoever they are, is the most repeated line in the whole song (one only hears the anthem first verse during public events but the whole song currently has seven of them -- two are not part of this video).
One has to understand the reason and circumstances that gave birth to the Marseillaise that originally was called "Marching Song for the Army of the Rhine Volunteers" or "War Song for the Army of the Rhine" before briefly becoming "Song of War for the Armies at the borders" (all temporary titles that didn't last long). Back then, in 1792, France was attacked from all sides by most of Europe monarchies that wanted to bring down the revolution and revolutionary ideals fearing that the French revolution would spread and end their own regimes (they weren't wrong although that didn't really happened until 1848 more than 20 years after Napoleon's death). France had no allies and couldn't count on any external relief so the song was written to inspire the whole of France to fight for freedom and the Republic against what seemed like impossible odds. With that in mind, here's the whole Anthem (minus a couple of verses) with the English translation:
The message to the enemies of France was pretty clear: "You want to take us on? Try it and see what happens. You might win but you'll most likely lose. France is standing against you, not just her army." This was a ballsy move, because the total forces of France were outnumbered and the royalist counterrevolution still happening in Western France held up a considerable amount of republican troops that could have been used elsewhere. Nevertheless, it worked thanks to some very good Generals and a lot of luck.
There are two other much less known French anthems and in their own ways, they are nearly as savage as the Marseillaise.
First we have "Le Chant du départ" (The song of departure) that was adopted by Napoléon Bonaparte as the national anthem of France during the first French Empire. La Marseillaise (that became the national anthem of France in 1795 then again in 1830) was originally a revolutionary song and Napoleon wanted to put as much distance as possible between the troubled and terrible times (with all the head chopping) of the revolution and what he was trying to achieve. Unlike what seems to be popular beliefs, Napoléon never banned the Marseillaise, it was just relegated to a secondary role. Still the lyrics of "Le chant du départ" are strangely brutal too...
Also, the word "slave" is used several times in this song (also in one verse of the Marseillaise) but is not to be taken literally. In this case "slave" means the people who are blindly following their leaders, submitting themselves to the old feudal system and so putting themselves in a position of servitude. It was the very early version of Bioshock Andrew Ryan asking what's the difference between a man and a slave and answering himself "a man chooses, a slave obeys".
And then, you have possibly the least known of the anthems composed in France, that is, the least known by non-French people, "Le Chant des Partisans" (The Partisans' song). This one was the unofficial anthem of the French resistance during WW2, the anthem of the France that was fighting the occupant. And what do you know, it is as savage as the two previous ones.
For the trivia, the image in the video is from the movie "Paris Brûle-t-il?" (Is Paris burning?). You see a resistant full center with a Sten gun (because this is mostly the weapons that were dropped by the British for the resistance -- my dad had one). The guy on the left which appears to be wearing an American uniform is not American. The first allied soldiers arriving to support the resistance in liberating Paris were from the Third Army under the command of Patton, but they belonged to the 2nd Armored Division which was all French. That caused some amount of confusion among French civilians that couldn't understand how so many Americans were speaking French without any accent. It's only when one of those "GIs" told them "I was born here, just a couple of streets away" that this particular fog of war began to lift. American units also came but a day later because liberating Paris was not in Patton's original plan (the original plan was to rush to Germany ignoring everything on the side and Paris was not on the way so not part of the plan -- and even though I'm French, I understand his reasoning here). For political reasons however, he finally accepted to divert the 2nd French Armored Division to help in the liberation of Paris, and that was only because it was a French unit. Then he sent a bunch of American units as an afterthought, possibly under pressure from his superiors: "For crying out loud, we can't only have French troops there". XD
I don't know what it is with France and her anthems, national or not, for the past 230 years. At one point, during the monarchy, France anthems were dull, very subdued, with no flamboyance to them and always without lyrics, then France decided to go "Rock and Roll" with a side of blood and the occasional slice of mayhem. :D
I'm not sure if any other anthem in the world is as bloodthirsty and grim as the Marseillaise, if I look to the national anthems I know, I'd say no, but there are many anthems in the world that I don't know (at least not the lyrics) so maybe some might compete.
The Marseillaise was not limited to France either. The song was borrowed and adapted with other lyrics and arrangements by other countries. Most prominently the Bolsheviks had their own Russian version of it during both the Russian revolution of 1905 and 1917 titled "The Marseillaise of the workers" before finally replacing it by "L'internationale", another French revolutionary song, which lasted as anthem of the USSR until WW2 when Stalin decided to replace it with a pure Russian song that became the most known USSR anthem of the Cold war (and is still today the national Anthem of the Russian Federation, personally chosen by Putin, with different lyrics).
In China, Mao used a version of the Marseillaise during the Long March of 1935 and the song was thereafter taught to Chinese children in schools until the 1970s.
Chile had briefly its own version of the Marseillaise as an anthem from 1970 to 1973 when the dictator Pinochet banned it after having his predecessor killed.
Even the Nazis didn't dare to suppress the Marseillaise during WW2 fearing that it might be the final straw leading to a global insurgency in France. Instead, the collaborative regime of Vichy had it "adapted" to better serve the needs of the new collaborative motto "Work, Family, Motherland" that replaced the original "Liberty, Equality, Fraternity". So for a few years, France had two Marseillaise, the original one used by Free France and the Free French Army and a "corrupted" one used by the Vichy Regime.
The list of the Marseillaise adaptations in songs and video games is impressive, even if sometimes it's just the use of a few bars like in "All you need is love" by the Beatles. A number of French singers also used it with modifications more or less respectful. One of the best use of the Marseillaise in a song was "La Navale" (https://youtu.be/9VVu98uAwyg?si=w5hEB5F7HqJlJIKV) by the French singer William Sheller (don't be fooled by the name XD ) in which the chorus is essentially the Marseillaise with altered lyrics.
It has been argued (in France) after WW2, and still today, that the Marseillaise is not an appropriate anthem for peacetime and that is likely true (I certainly didn't think it was, growing up). But sadly history proved to us time and time again that war is never far, mainly because history is a great teacher but humanity is a horribly bad student. Like our President told us a few months ago (when he increased the military budget) "If we want to remain free, we have to be feared". Not sure this is the best argument to make, and I'm pretty sure it's not the most enlightened one, but considering recent and current events, I'd say he sadly does have a point.