Se balancer means "to swing" or "to sway". While it can refer to physically swinging, it often carries a more nuanced meaning of being carefree, indecisive, or even emotionally unstable.
In the context of the song, the singer wonders if she's been replaced by "Quelqu'un qui aime se balancer" (Someone who likes to swing/sway). This could imply someone who is more playful, less grounded, or perhaps someone who easily moves from one thing to another, contrasting with the singer's more stable, yet heartbroken, state.
This song feels like a lonely Christmas card that will never be sent. The singer, Pomme, finds herself in a cold Montreal, thinking about someone who is no longer in her life. She knows they won't come back and won't reply, but she can't help but wonder what they're doing for the holidays.
She looks back on their relationship, which she saw as a "refuge," a safe place. Now, she feels like she's drowning in the silence left behind. The lyrics reveal a deep sense of loss and confusion, as she asks, "You never loved me / How can I hate you?" It's a bittersweet and melancholic reflection on a connection where one person gave all they had, only to realize it might not have been love at all.