Drouillet was one of those 'Stream of Consciousness' painters who is difficult to classify. Maybe 'Expressionist' would suit him the closest; but it's not ideal.
Like many, he started each job with a simple idea, then filled spaces to create composition; colour then balanced where his subject matter was lacking. We all do it, but he had a particularly interesting format.
He used what I think of as 'devices' to fill his canvases; the one below being a good example. Plants, leaves, flowers, and unknown objects.
I have only recently discovered that M Drouillet died back in 2011; at 65 he was a relatively young man.
A good painter; worthy of further investigation.