Galères is a very popular French slang term for "hardships," "struggles," or "troubles." While its literal translation relates to the 'galleys' (old ships rowed by prisoners), it's now used informally to describe any difficult or messy situation.
In the song, GIMS sings "Tu me suis partout, et même dans mes galères" (You follow me everywhere, even through my struggles). Learning this word is a great way to make your French sound more modern and authentic!
In "CIEL", GIMS tells a story about a relationship that feels both magical and doomed from the start. He talks directly to the sky, complaining, "Ciel, tu n'm'avais pas dit qu'c'était une magicienne" (Sky, you didn't tell me she was a magician). He sees this woman as an almost supernatural force who just "tombée du ciel" (fell from the sky), but he also expects her to cause trouble.
The song mixes images of luxury and anxiety. One minute he's having a nightmare about being broke, the next he says, "J'ai retrouvé la vue dans le Ferrari vert" (I got my sight back in the green Ferrari). But all the money and magic can't fix the relationship's core problems. He admits to lying and pretending, and realizes that "la vie n'est pas comme tu crois" (life is not what you think). In the end, it's a story about a beautiful but broken connection, where all that's left are memories and the pieces of glass on the floor.