The Prussians absolutely didn't have such pennons at this time, although they adopted something of the sort before World War One. For the French in 1870 it's less clear. No system of command "fanions" was prescribed by regulation until 1876, but certainly some generals did have them in 1870. I think an unofficial system had developed, probably in North Africa, and the 1876 regulations confirmed it. Photographs and well-researched paintings show that some corps and divisional commanders had these fanions, but we don't know if they all did. I don't think brigade-level commanders had them, as the 1876 system only prescribed flags for divisional commanders upwards. The fanions we know of in 1870 are plain tricolours for corps commanders, and vertical red and white stripes for infantry division commanders. The stripes were of equal width: one red stripe for the first infantry division of a corps, two for the second and three for the third.