Sorry to bring up an old thread, but I thought I'd update on this, nearly a year late! I didn't want to put too much information in the public domain at the time, but I appreciate the comments.
So yes, I hired the car from Europcar (good guess!). I had a disagreement with the check in people when I returned the car due to the above damage, which I fully disputed. Europcar then sent me an invoice for EUR 0.00 saying something like "nothing further payable."
After that they sent a first letter demanding around 1000 EUR which included replacing the bumper - you can see it's not damaged in the slightest! I told them to bugger off - they then sent a second letter, again demanding around 1000 EUR. I sent them a scan of the invoice showing 0.00 EUR payable, again telling them to bugger off, including numerous complains about the hire. Trying to claim for a new bumper is simply fraudulent.
I've heard nothing since.
So, lessons are:
a) Be very very very very careful when renting a car - even when you thought you were careful.
b) Never hire from Europcar
c) Dispute the damage, take photographic evidence (I did) and use their crapness against them
I've had some great hires from Hertz in the mean time from the same airport (Berlin Schoenefeld) - including getting upgraded from an Opel Meriva at an already dirt cheap price for a 4 day hire to an InfinIti FX (luxury Nissan 4x4 - complete chelsea tractor, but great for cruising on the autobahn) for only 10 EUR
The Opels are really under powered and really drink petrol at about 90mph on the autobahn.