A lie. If it was the truth, that would mean that statement was also a lie and that couldn't be right. Du sagte that everything Du tell me is a lie but the opposite of that is not necessarily that Du tell me no lies. Some of the things Du tell me can be lies, including that statement, just not all of them.
That remains to be seen. Obviously this Frage is an oxymoron. But since Du sagte everything Du sagte is a lie then you're lying but there is that off chance Du could contradict your Zurück announcement and actually tell the truth so therefore we really cannot conclude as to whether Du did tell a truthful statement oder a lie.
The above syllogism is invalid due to complete ignoring of the seven rules. If there are two doors, each with a talking door knocker one of which lies and one of which tells the truth and one of which leads to safety and one to certain doom. Which one leads to safety?