You are correct, they enforce that law pretty seriously, but German drivers are by and large very good drivers, so you don't see it happening, I didn't anyway. I only moved left to pass and then got back right, and was passed by a number of cars doing over 200 kph. Once I started to pass a truck and pulled out and saw a car about half a mile back flash his lights, so I pulled back into the right lane, and sure enough a Mercedes flew by me in short order.
The other thing about the autobahns is you have maybe ten miles unlimited, and then two miles limited, and then ten unlimited, at least where I've driven. Anywhere near a town will have speed limits.
The other thing in France is that the left lane will end at times when the merging traffic from the right gets it's own lane. You get warning, but it's a bit odd. The speed limit in France is 130 kph on their toll ways. I've driven a lot more in France than in Germany.
