They are instructions to the civilian population on how to behave towards prisoners of war in labour detachments. Germany used millions of prisoners of war as forced labourers in agriculture as well as industry where they came into daily contact with the German population. There were strict rules surrounding contact with POWs and this poster outlines those rules. I am a bit too lazy to translate the whole thing word for word, but here are the bold bits:

The enemy always remains the enemy

Maintain the utmost reserve towards prisoners of war!

All fraternising is a betrayal of our frontline soldiers!

Do not barter with prisoners of war!

Do not allow German money to fall into the hands of prisoners of war, it would facilitate their escape.

Consider the danger of sabotage!

Consider the danger of espionage!

Do not therefore deliver mail for or to prisoners of war

"Unless contact with prisoners of war is inevitable in the performance of one's duty or profession or in an employment relationship, any contact with prisoners of war and any relations with them are prohibited.

Anyone in breach of these regulations will be severely punished.

Aid in escaping and conveying secret messages [missing text] treason will be punishable by death.

Wow! Thank you so much!! I'm much more happier now than I already was when I found it!!