What are the functions you want in this space? Will there be a dining table as well as a seating area? Both of those should be fairly grandly sized. What else?

The key to dealing with large rooms is to creating zones. Start with painters blue tape to tape off and identify zones. (living, dining, kitchen, etc.) You can distinguish them with carpets, painted walls, art, and furniture. Make sure your seating areas are intimate and close together, and "floating" in the room (not close along a wall).

The only reason I can think of why someone would want a 200m2 space for a
living and dining room is because they like space. ;) So I think you
should enjoy the empty space. I would probably just do 1 seating area
based around a very large area rug, this can be made really cozy with
the right decor even though it's "floating" in a large space. Then some
distance from this seating area would be the large sort of sculptural
dining table and dining area. Somewhere could be a large scale art work.

As a side note it's nearly impossible to give any half decent concrete advice based on this one picture so I'm just throwing ideas in the air really.

One thing to think about in a space this large is the acoustics. They're going to be insane! Plush area rugs and window treatments will help.