Baladé comes from the verb balader, which literally means "to stroll" or "to take for a walk". However, in this context, it's used in a more colloquial and figurative sense.
Here, "Tu m'as baladé" means "You led me on" or "You strung me along." It perfectly captures the feeling of being deceived and manipulated in a relationship, making it a very relatable and impactful word in the song.
"Baladé" is a breakup song about being led on. Vitaa sings about trusting someone who turned out to be careless with her heart, letting him have his fun while she stayed fragile and docile until he broke the deal.
The chorus repeats "tu m'as baladé, tu m'as bazardé" — he strung her along and then tossed her aside. She admits she gave everything and forgave too easily, but now she's done: the "bye bye" refrain marks her walking away for good, no longer the naive one who let herself be pushed around.
By the end the song turns into a chant, with the repeated "baladé" hook becoming almost a release — less an accusation than a way of shaking the hurt off.