OP read this, they're absolutely right - lawyer up!

Cause in the U. S. if you want to renounce your U. S. citizenship, you must settle your debts - which includes filing your U. S. Taxes.

... and yes, as a U. S. Citizen you need to file U. S. Taxes *even if you've never set foot in the U. S. *.

Note: there are double taxation laws between the U. S. and Germany, which prevent you from needing to pay taxes in U. S. (up to 100k / year or so), but you still must file them.

Also, as a U. S. Citizen, you'll need to file annually a FBAR with the IRS. This is basically a disclosure to the IRS that you have non-u.s. bank accounts (that exceed, in total, 20k usd / year).

The point being is that, in theory, there could be fines for not doing this, which (in theory) you would have to pay before being allowed to renounce your citizenship.

In practice, the IRS is pretty approachable - so you probably won't have an issue, but you'll definitely want decide if you want to keep the U. S. Citizenship (and the work associated with it: annual taxes and fbar) or renounce it.

The (only) upshot of filing U. S. taxes abroad if you have kids is that you qualify for a Child Tax Credit. Which amounts to 1000 usd / kid / year (I don't know if the kids need to have U. S. Citizenship or not)