Although Bach's works have a BWV number, some of them are called spurious or doubtful. This small fugue is mentioned as being spurious. So Bach didn't write it. Gottfried August Homilius is mentioned as the composer. Since he was a very fine composer (check out his bundle of chorale preludes!) it's still a pleasure to play this small gem.
This piece was a nice excuse to satisfy my 'flute 4 addiction', certainly with such a fine Holzflöte from the Metzler organ of Poblet.