The following is from the article on Golo Mann (1909 – 1994) in the German Wikipedia (translation courtesy of Google Translate). Golo Mann was the son of German novelist and 1929 Nobel Prize in Literature laureate Thomas Mann (1875 – 1955).
In January 1933, Adolf Hitler came to power. For Thomas Mann, who had made no secret of his dislike of National Socialism, and in particular for Golo Mann's older siblings Klaus and Erika Mann, this was the time to emigrate. While the parents were staying on a lecture tour abroad, of which she did not return to Golo Mann attended in April 1933 at the Munich House, organized the departure of three younger siblings and brought the bank balances of the parents to safety. Thomas Mann asked his son bundle of notes and oilcloth notebook - they contained Thomas Mann's diaries of the Twenties - to stow away in a suitcase and means of forwarding by rail to Lugano to send with the urgent request: "I count on your discretion, that you are [not going to read them]."
Hans Holzner, the driver of the family and secret follower of Hitler, offered to give up the case. Instead, he handed over the bag of the Bavarian political police. When it was still not arrived three weeks later, the seizure was near, and Thomas Mann implored the lawyer Valentin Heins to try anything to [obtain them back]. Golo Mann describes the panic came into his father: "[They] will publish it in the People's Observer. [They] ruin everything, they'll ruin me. My life can not be all right." Heins reached in negotiations a few weeks later [their release].
Do we know what Thomas Mann (via his attorney Valentin Heims) yielded in these negotiations with Hitler's Nazis? (The article cites Golo's Mann's autobiography, which I do not have ready, as source for the last sentence.) I assume its fair to refer to negotiations with Nazis, because the article identifies the driver as a follower of Adolf Hitler. Thomas Mann was about to emigrate to the U.S.