The idea of Panzer grey was that when the vehicle was stationary, it would halt in shade and blend in. Same reason the British painted vehicle roofs black. If it was moving, you’d see it anyway, though in the 1930s the scheme was actually dark grey and red brown disruptive, same as many German WW1 vehicles. In northwest Europe, dark colours are good (forests, shade) , which is why Bundeswehr NATO green was so dark. When Adolfs boys rolled across the Ukrainian steppe though, they noticed that parched grassland is a sort of dun brown colour and somewhat devoid of dripping North European pine forests, so dunkelgelb is a good match. Further north though, plenty of dank forests, so they had pots of green and brown paint to mix it up a bit. The US and British weren’t planning on fighting in the Ukraine, so painted their tanks greenish. The Russians went with dark/mid green as a good base colour and largely relied on natural camouflage, although in the south some Russians also adopted sand/green disruptive paint schemes. All countries advised their tank crews to park up in shade, vehicles are far less conspicuous from both air and ground observation. The Italians, Hungarians and Japanese had quite jazzy colour schemes, as did the Finns.
Any explanation for why the French went even ‘jazzier’ with many of their schemes?
Less enthusiasm, please. This is Britain.