"La Marseilles" really is a very stirring & powerful tune, but the lyrics are especially bloody and militaristic.

Here's an English translation:

Arise, children of the fatherland!

The day of glory has arrived.

Against us tyranny's bloody standard is raised.

Do you hear, in our fields,
 these fearsome soldiers roar?

They come right into our midst

To cut the throats of your sons, your consorts.

To arms, citizens!

Form your battalions!

March, march

Till an impure blood
 waters our furrows.

What do this horde of slaves,

Of traitors and conspiratorial kings, want?

For whom these vile chains,

These long-prepared irons?

Frenchmen, for us, ah! What outrage,

What feelings that must excite?

It is us they dare plan
 to return to the slavery of old!

What? These foreign cohorts!

They would make laws in our courts!

What? These mercenary phalanxes

Would cut down our warrior sons.

Good God! By chained hands

Our brow would yield under the yoke

Of the vile despots who would become
 our intended masters.

Tremble, tyrants and traitors,
The shame of all parties!

Tremble! Your parricidal schemes

Will at last receive their reward!

All are soldiers to fight you.
If they fall, our young heros
,
France will bear new ones

Ready to do battle against you.


Frenchmen, as magnanimous warriors,

Bear or hold back your blows!
S
pare these sad victims

Who regret taking up arms against us,

But not these bloodthirsty despots,

These accomplices of Bouillé,

All these tigers who mercilessly 

Ripped out their mother's bosom!

We shall enter into the pit

When our elders are no longer there.

We shall find their ashes
 there
And the traces of their virtues,

Much less jealous of surviving them

Than of sharing their coffins,

We shall have the sublime pride

Of avenging or following them.

Sacred love of our fatherland.

Lead on, support our avenging arms!

Liberty, dear Liberty,

Fight alongside your defenders!

Under our flags, let victory

Come quickly with your manly strains
So that your dying enemies

See your triumph and our glory!