Police controls during professional traffic

Hello! I was stopped last week Tuesday morning on the way to work by the police. General traffic control in a parking lot, probably mainly for still alcoholized carnivalists. I was just not strapped. Wars now from the Penalty Office Post. I arrived through the whole thing (two drug tests were carried out, of course negatively) considerably later at work. I once “heard” that there should be a paragraph, which should give the professional traffic In my research on the net, however, I did not find out. I am still thinking about whether to file an objection. Thank you in advance for your comments! Many greetings