"Luxemburgues" is a love song made almost entirely of images. Estelares sing about the sea, "azules corales azules" (blue corals, blue), sand, stones, asphalt and hills, and drop them next to each other like snapshots. You do not get a story so much as a feeling of being somewhere new with someone.
The chorus is the clearest part: "Sólo sé que me enamoré" (I only know that I fell in love) and "Tu nombre no es un nombre más / huele a jardín luxemburgués" (your name is not just another name, it smells like a Luxembourg garden). That garden line is a lovely odd detail, a very specific, faraway place used to say this person feels special and a bit exotic. Then comes the change: "Ya no soy gris" (I'm not grey anymore). Love has coloured him in.
It is not all soft, though. "Hielo y sal, me queman tus labios" (ice and salt, your lips burn me) and the closing "a incendiarme mi amor" (to set myself on fire, my love) make it clear this is a love that burns. Watch the phrase "un nombre más": "más" here means "just another", a really useful pattern.