Paint the walls a bright color if you have a small room, as a bright color will help to open up the room in combination with a bright red sofa. If you have a dark red sofa, a light color will help to keep the room from feeling claustrophobic. Bright white is a safe choice if you are unsure of what type of décor you will be using when you paint.
Use dark colored paint for a large room like a formal dining or living room that you want to give an elegant feel to. Use lights on dimmers or wall sconces for low, warm lighting and consider heavy, pleated draperies instead of shades or blinds for a bold look.
Put a light colored rug down on the floor if you have dark colored floors. A red sofa and dark floors will start to look like one big block of saturated color; adding a light colored rug will help to break that up. You don’t have to stick with white or solid colors for a rug — crème, beige, light blue and light colored patterned rugs can all add depth and space to your room.
Make sure your room has plenty of lighting to avoid making it feel too dark, especially if you are using other highly saturated colors like deep yellow, brown or black in a room with a red sofa. Use task lighting and decorative lamps instead of relying solely on track or recessed lighting to light all areas of the room.