What were the restrictions put on Germany after world war 2?

Germany did not exist post-WW2 until reunification in 1989.

Neither West Germany nor East Germany (created out of the US/UK/French occupation zones and the Soviet Occupation zones) were allowed to independently sign treaties, nor have armies.

This changed rapidly with the onset of the Cold War.

The worst that happened to Germany was half of it was granted to Poland, with 11 million German civilians expelled or murdered by the Polish and Soviet armies.