https://fbcdn-sphotos-c-a.akamaihd.net/hphotos-ak-ash3/31016_10151125107486404_1180171551_n.jpg

See that banner in the distance? Well, look here: http://images.uesp.net/4/43/HouseHlaalu_flag.png

That banner belongs to House Hlaalu. And I'm guessing the place in the screenshot is Raven Rock, or Fort Frostmoth. It is interesting to see however that the architecture is similar to House Redoran's, as is the Bonemold shoulders. It is possible that the Great Houses have united, which would make sense, given the fact that they are severely weakened compared to how they were in Morrowind (and they sometimes unite under unique circumstances).

the architecture seems distinctly Redoran to me. i think the banner could pass for a generic merchant sign.

That is Redoran architecture... I also think it's just a merchant, but who knows? Maybe the Redoran let some Hlaalu in.

I think it is a Hlaalu representative house. I think the Dunmer put aside their differences... they were ALL trying to survive. To me ITs a Hlaalu flag, but the theory of Hlaalu flag being left as the representation of the commercial buildings is plausible.
But, besides that, the guard is Redoran, the city (as we see the flags on the wall in the trailer) is under Redoran Rule.
The good news to Redoran fans as me, is that House Redoran is STILL ALIVE!