Why is the French national anthem called La Marseillaise?

the "chant de guerre de l'armée du Rhin" (the original name) was popularized by the volunteers' regiment from Marseille (and whereabouts of Marseille). It became known informally as 'le chant des marseillais' and after that 'la Marseillaise', even thought there isn't any link between Marseille and the lyrics of the song.