It seems that the first time I went to Pottoka was about 3 years ago and it had been open for a while even then. Has Pottoka really only been open for 2 years?
Robert et Louise is OK for steaks. I think that there might be better places, I should suggest:
Au Boeuf Couronné
le Severo
Le Louchebem
Bistro Paul Bert
la Cordonnerie
I have had a number of outstanding steaks at restaurants that were not specifically noted as beef restaurants, such as at Bistro Paul Bert. Most of the locations I mention will require reservations well in advance.