I'm at @EUCourtPress following Facebook v Belgian DPA. At stake: the scope of the one-stop-shop (GDPR mechanism by which regulator where company has EU's base takes the lead on investigation). Stay tuned.

First up, Facebook. it argues that single point of contact is a "vital aspect" of the regulation, and that in GDPR do not apply. "The distinction that the Belgian DPA makes between administrative and legal proceeding is artificial."

Facebook counsel says any legal action brought by the regulator would have to be preceded by administrative proceedings. Says Belgian DPA's argument risk causing a "huge rise" in number of court proceedings a "judicial fragmentation" — which GDPR was supposed to end

Belgian DPA up next, argues that it made "serious attempt" to cooperate with Irish DPA (Facebook's lead) before taking legal action. "Nowhere does it say [in GDPR] that lead authority exclusively competent."

Belgian DPA also rejects Facebook argument that its argument would lead to "a rush on the courts". Points out that the judicial route will always cost money.

The European Commission broadly backs Facebook. Disagrees with Belgian DPA notion of the lead authority solely in coordinating "steering" role. "That does not do justice to definition of lead authority in the GDPR."

Commission hints at split between EU member countries in understanding of one-stop-shop. Commission counsel seems to indicate that Belgian and Polish governments back Belgian position.

Commission counsel: Better when we have one strong position, rather than 27 different positions. "These are European rules at the end of the day."

AG M. Bobek asks the big question: What provisions are there in the GDPR to deal with "regulatory inertia"? Commission responds that that is where regulator grouping the EDPB comes in, describes approach as "collegial"

Commission cites Max Schrems as example of GDPR allowing citizens across EU to complain against multinationals. AG M. Bobek with a putdown: "And Max Schrems is your example of a normal consumer?"

ECJ pres. K. Lenaerts asks Commission: "You're saying people could go to court, but that the DPA cannot take up their cause? So you have Joe commoner who can go to court but an authority can't take up his case for him?"

Commission refutes Lenaerts's characterisation of authorities as weak because they can't go to court. Says that they can disagree within the structure of the EDPB.

Belgian DPA piggybacks on Lenaerts' Joe commoner line. "It seems illogical to us that if the man on your street wants to go to court against Facebook, suddenly the authority cannot intervene? So then the man on the street is left on his own, and DPA cannot play a role."

AG Bobek opinion expected on December 17

Quick take: Court esp. Bobek — who will write opinion — and Lennaerts seemed v sympathetic to the Belgian DPA's position. Both questioned why watchdogs designed to look out for citizens' privacy would be cut out of legal proceedings