Tusk is a crook, those folks have the goods on him, and he knows it.
Germans know how to put the ‘squeeze’ on other countries:
“In late May 1933, the German government announced an economic sanction against Austria. This sanction was referred to as the ‘1,000 Mark Sperre.’ It required Germans to pay a 1,000 Mark customs fee in order to travel to Austria. This crippled Austria’s tourism industry, which was highly dependent on Germans. “
https://encyclopedia.ushmm.org/content/en/article/nazi-territorial-aggression-the-anschluss