When in doubt wear red. - Bill Blass!
photo by Tria Giovan.
I guess Valentino would agree with that quote. Red has always been associated with glam and splendor and it seems there is no rule of thumb to make it work in any type of interior. Either in softening up a near by iron spiral staircase or adding that certain "Je ne sais quoi" to a mid-century space as in Mac Jacobs' Paris home in the last, far bottom picture.
top image from via Costal Living, 6 via Pink Lemonade , last Marc Jacobs Paris' apartment via Moodboardphotographed by the late Fernando Bengoechea.