The F on the frame is confuzzling me a bit. According to this: My Austro-Daimler "Vent Noir II" Bicycle And Brief History of Steyr Daimler Puch, the F SHOULD indicate that the BB is french threaded, but the Shimano that's currently in there says otherwise. The F should also be on the underside of the lug. The way I knew mine was English was by the knurling on the Nervar lockring, but that doesn't apply here. I would pull the fixed cup to be sure. I would bet on it being English, but Velo Orange sells french threaded bottom brackets.