This paper presents a study of the articulatory properties of French vowels using an acoustic-to-articulatory inversion method. The advantage of such an approach is that all the possible articulatory configurations can be studied independently of any articulatory preferences linked with a given speaker. Furthermore, it bypasses the issue of acquiring a vast amount of articulatory data by medical imaging techniques. The inversion method exploits an articulatory codebook, the acoustic precision of which is constant whatever the articulatory reion considered. Since the inversion is performed from the first three formants of vowels to recover the seven parameters of Maeda's model the null space of the articulatory to acoustic mapping is explored to recover all the possible articulatory shapes. Applied to French vowels this method allows the different places of articulation to be determined.