30 square meters (about 270 square feet) should be fine.
I do think these speakers prefer a relatively well/damped or "dead" room. If you don't have carpet and not much soft furniture, you might find they sound a little bright in a room of that size.
My room is about 16 x 22 x 9 feet, and I found that I needed to add absorption panels to tame the reflections. I don't have much furniture, and just an area rug.
