In French language, "coach" was traditionally used to describe 2-door cars with 2 side windows (on each side), while "coupé" was used for 2-door cars with 1 side window (on each side). This was mostly true before WWII, then it got blurrier, "coupé" being used more and more often for what used to be called "coach". Then, from the mid seventies up to the late eighties, "coach" was often used for 3-door hatchbacks like Polos or Renault 5s. Now I rarely see it used.
So technically this car is a "coach" in the old-fashioned way, but calling it a "coupé" is not improper nowadays.