Carteles literally translates to "posters" or "billboards". It's an interesting word because it's central to the song's narrative, representing the omnipresent image of a past lover.
In the song, the singer repeatedly sees her ex-lover's image on "carteles" throughout the city, making it impossible to forget him. This word captures the unique and somewhat haunting experience of seeing someone you're trying to move on from plastered everywhere, turning everyday objects into symbols of lingering feelings.
Daniela Spalla wrote "Carteles" about the strange grief of loving someone who becomes famous. She isn't running into her ex, she's seeing their face everywhere. "Salí a despedir un mal de amores" [I went out to say goodbye to a heartbreak], she starts, and instead of closure she gets billboards: "Te vi en los carteles en la calle" [I saw you on the posters in the street], "vendiendo tantas giras y canciones" [selling so many tours and songs]. It used to be personal, close enough to see from home: "Brillabas a unas cuadras de mi casa" [You were shining a few blocks from my house].
The rest of the song keeps returning to one idea: the person she loved is now something sold. "Vendes desde tu cartel" [You sell from your poster], she repeats, "un romance que derrite la vereda" [a romance that melts the sidewalk]. It's a line for strangers, not for her, and she knows it: "Vendes, pero sé que luego partirás cuando me duerma" [You sell, but I know you'll leave when I fall asleep]. By the last verse she isn't asking for anything back, she just lets go: "Te dejo esta canción para que sueltes nuestro amor" [I leave you this song so you let go of our love]. It's a breakup song for a very specific, very modern kind of heartbreak, grieving someone in public, one poster at a time.