A bridge over Schengen’s troubled borders

In June 2017, the Court of Justice for the EU issued a decision on the activities the German Bundespolizei was deploying in the French-German border area. Were these activities Schengen-proof police checks or permanent border checks in disguise?

A bridge over Schengen’s troubled borders Source: Arnoguerber [CC BY-SA 3.0] / Wikimedia