“How can we follow up on an agreement without upsetting our German colleagues?”
First, ask yourself when is it truly necessary to do follow-up. Americans do a lot of follow-up, often purely out of nervousness and anxiety.
Second, when entering into an agreement with your German colleagues, discuss and agree on the frequency of follow-up. Be sure to point out to them the American logic regarding follow-up.
Sensitize them to the cultural difference. While doing so allow them to sensitize you about their German logic.
Third, when following up with your German colleagues simply ask them if you are upsetting them. Yes, literally ask them. Give them a chance to signal what the right frequency is. At the same time, explain to them the parameters within which you are operating, which, in turn, require follow-up.
Fourth, at an appropriate time reach out to your German colleagues and ask them to explain to you how Germans fundamentally handle follow-up. Ask them literally what the German logic is. Chances are your German colleagues will ask you about the American logic.