Interesting post... I recently had flip flops on and realised when I went to drive the car that I didnt feel I had total control of the pedals, so I drove barefoot!
Regardless of whether the law allows it, does common sense? I can't safely control the pedals wearing flip-flops, and have no idea how anyone else could.
According to this article it wasn't forbidden in 2007 and this one in 2008 says the same thing - HOWEVER - if you are involved in an accident and it can be shown that your footwear or lack of same had anything to do with it, then it comes under 'the driver must ascertain than nothing hinders his driving'.
No, it actually says that you can get fined in a routine check if the police considers your shoes unsafe to drive a car.
It seems to be "grob fahrlässig" to drive barefooted or with open heels. So you can theoretically get fined for it and if you crash you are in deep trouble.
I live in my fitflops and drive in them all the time. I have never even considered that I don't have full control of the pedals, perhaps because they have a much thicker sole than regular flip flops. I know that I had some ballet style pumps that I never drove in as they had zero grip...
I think it depends upon what you usually wear how safe you feel.
Living in Florida for so long, "everyone" wears sandals of various types all the time, including thong / flip-flop style. I never had any issues driving with these style shoes.
Some of my party shoes on the other hand (something roughly like this ) were a bit of a challenge since I did usually wear flat shoes.
I can understand why this would be so here as folks do not wear those sort of shoes as often... one reason why it is important to know local regulations.