The Germans took an early lead through France international Kingsley Coman.
Ryan Sessegnon showed great composure to score his first goal for Spurs to tie the scores after 20 minutes.
Speaking after the game, Spurs manager Jose Mourinho said he learned a lot from the match.
He told BT Sport: "A good match for me. I don't want to speak about conclusions because it is too strong a word but I would say important information. I give you clearly a positive example because they are easier.
"Today I learned a lot about Juan Foyth. He didn't play one minute for me until today and I learned more in these 90 minutes than I did in two or three weeks of training. No conclusions but good information.
"I would prefer to win or to draw and for Son to score in the last minute and lose 3-2 rather than 3-1 of course but we knew the match was important for other reasons. We didn't want a result that leaves a shadow on us but I think positive things about many of the boys."