He's not that obscure, not among singers, at least. His principle area of success was in melodie, French "lieder," and I have a recording of the late great French singer Gerard Souzay singing a number of these. As a matter of fact, I think these are the only important works he wrote. I would say his style is reminiscent of Chabrier.
BTW, isn't it funny how many lieder and song composers who are common names among singers remain completely unknown by other musicians? For instance, most musically educated pianists have never even heard of Roger Quilter, whose output is a truly wonderful and important addition to English song reportoire, particularly his settings of Shakespeare songs. Hahn, too, remains largely unknown outside the song world. Why is this? It's funny when we are constantly reminded to "sing" at the piano, and Chopin tells us to listen to great singers not great pianists for study, that most instrumentalists know very little about the singing reportoire.
Topic: Has anybody heard of Henri Duparc??