The main fan zone area in Berlin will be directly in front of the Brandenberg Gate.

The city authorities are dubbing it the "mother of all fan miles"! They're going to erect an enormous 'goal' in front of the Gate itself and completely close off the road that runs through the Tiergarten from the Gate towards the Victory Column. That's the Street of the 17th of June (Strasse des 17. Juni). 

Along the street they'll be laying artifical grass and creating a 'pop-up park', with numerous big screens and outlets selling food and drink.

All Germany games plus many others will be shown.

I've watched a few games there in the past, and it was certainly an impressive set-up with space for tens of thousands.

More info here: Berlin Euro 2024 Projects and here Berlin Fan Mile