Besides, the article only says that this is being considered and that talks (probably) haven't even started yet.
Up to recently, the German cabinet claimed to be content with the affirmation of U.S. officials to only work within the boundaries of German and U.S. laws.
The level of blind trust in "our allies" was astonishing, for example they called allegations backed by the Snowden documents "unfounded".
Few months ago they've sent a few secretaries over to negotiate an non-binding letter of "no spy" intent, that the U.S. obviously didn't want to agree to (because no autonomous state would).
So, now they finally seem to have come to the conclusion that indeed we (as a state) are spied upon, for a myriad of reasons, which is quite an accomplishment for these naíve guys and girls.